sandbox: allow "make ARCH=sandbox allyesconfig" ...

Compiling the tree with allyesconfig is helpful because different
compilers (gcc, clang) or static checkers (e.g. clang's scan-build)
can then process and check more code.

This patch introduces two new configuration symbols that Kconfig files
can depend on. That way, code that is only working where a cache or DMA
implementation exists can be opted out.

Signed-off-by: Holger Schurig <holgerschurig@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

regulator: fixed: add always-on property ...

Support the "regulator-always-on" property for fixed regulators.
The regulator gets enabled on probe and subsequent disable calls are
ignored.

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Add initial regulator support ...

Provide minimal regulator support. Only supported operations are enabling
and disabling regulators. Association of devices with their regulators is
limited to devicetree only. If regulator support is disabled the API expands
to static inline stubs so consumers can still use the API.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>