dtblint: check reset-gpio-active-high + reset-gpio for matching polarity

fix leaks of memory returned by read_file() calls ...

Signed-off-by: Enrico Jorns <ejo@pengutronix.de>
Reviewed-by: Michael Olbrich <mol@pengutronix.de>
Signed-off-by: Roland Hieber <rhi@pengutronix.de>

dtblint: check for fec reset gpio polarity mismatch

dtblint: split out imx-pinmux checks

dtblint: fix a few swpad reset values ...

The reset values had bits set that were not in the writeable mask.

dtblint: don't accept 0 as config for a pad without config ...

The Linux driver fails on pinctrls that specify 0 as config, so
consequently flag this as error.

dtblint: fix test for non-existent config register ...

When off_t is a bigger data type than u32 the check (conf_reg ==
(uint32_t)-1) never triggers.

dtblint: silence unused-but-set-variable warnings ...

src/dtblint.c: In function ‘parse_function’:
src/dtblint.c:1153:12: warning: variable ‘input_val’ set but not used [-Wunused-but-set-variable]
   uint32_t input_val;
            ^
src/dtblint.c:1152:12: warning: variable ‘input_reg’ set but not used [-Wunused-but-set-variable]
   uint32_t input_reg;
            ^
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

dtblint: new tool to check device tree blobs ...

Currently it checks iomux nodes on i.MX25 only, but adding other i.MX SoCs
is just a matter of adding the corresponding table