This adds the following commits from upstream dtc:

60e0db3d65a1 Ignore phandle properties in /aliases
95ce19c14064 README: update for Python 3
5345db19f615 livetree: simplify condition in get_node_by_path
b8d6eca78210 libfdt: Allow #size-cells of 0
184f51099471 Makefile: Add EXTRA_CFLAGS variable
812b1956a076 libfdt: Tweak data handling to satisfy Coverity
5c715a44776a fdtoverlay: Ignore symbols in overlays which don't apply to the target tree
b99353474850 fdtoverlay: Allow adding labels to __overlay__ nodes in overlays
d6de81b81b68 pylibfdt: Add support for fdt_get_alias()
1c17714dbb3a pylibfdt: Correct the FdtSw example
ad57e4574a37 tests: Add a failed test case for 'fdtoverlay' with long target path
bbe3b36f542b fdtoverlay: Rework output allocation
6c2e61f08396 fdtoverlay: Improve error messages
297f5abb362e fdtoverlay: Check for truncated overlay blobs
702c1b6c0e73 README.license: Update to reflect SPDX tag usage
4097bbffcf1d dtc: Add GPLv2 SPDX tags to files missing license text
94f87cd5b7c5 libfdt: Add dual GPL/BSD SPDX tags to files missing license text
c4ffc05574b1 tests: Replace license boilerplate with SPDX tags
a5ac29baacd2 pylibfdt: Replace dual GPLv2/BSD license boilerplate with SPDX tags
7fb0f4db2eb7 libfdt: Replace GPL/BSD boilerplate/reference with SPDX tags
acfe84f2c47e dtc: Replace GPLv2 boilerplate/reference with SPDX tags
87963ee20693 livetree: add missing type markers in generated overlay properties
825146d13dc0 Fix typos in various documentation and source files
25bb080c18d1 Update the GPL2 text to the latest revision
243176c4ce84 Fix bogus error on rebuild
ce01b21098a4 libfdt: Add FDT_CREATE_FLAG_NO_NAME_DEDUP flag that trades size for speed
fbb62754ce45 libfdt: Introduce fdt_create_with_flags()
228a44cce857 libfdt: Ensure fdt_add_property frees allocated name string on failure
8f695676227b Avoid assertion in check_interrupts_property()
5c3513f68921 Link tools and tests against libfdt shared library
00f9febf9c16 tests: Rename tests.sh to testutils.sh
c5d45188f923 Clean up LDLIBS handling
6ef8fcd05b74 Rebuild libfdt shared object if versioning linker script changes
26ee65a16c38 Use Python3 by default
cca6546244cb libfdt: Make fdt_get_max_phandle() an inline
730875016a6a libfdt: Add phandle generation helper
7dfb61ba96b1 libfdt: Use fdt_find_max_phandle()
2bc5b66d7f6c libfdt: Add new maximum phandle lookup function
7fcf8208b8a9 libfdt: add fdt_append_addrrange()
ae795b2db7a4 checks: Do not omit nodes with labels if symbol generation is requested
eac2ad495b29 Update version.lds again
f67b47135523 Revert "libfdt: Add phandle generation helper"
54ea41c22415 libfdt: Add phandle generation helper
4762ad051ee0 checks: Fix spelling in check_graph_endpoint

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>