Move this header out of the common header.

Signed-off-by: Simon Glass <sjg@chromium.org>

At present dm/device.h includes the linux-compatible features. This
requires including linux/compat.h which in turn includes a lot of headers.
One of these is malloc.h which we thus end up including in every file in
U-Boot. Apart from the inefficiency of this, it is problematic for sandbox
which needs to use the system malloc() in some files.

Move the compatibility features into a separate header file.

Signed-off-by: Simon Glass <sjg@chromium.org>

Signed-off-by: Tom Rini <trini@konsulko.com>

Add libavb lib (3rd party library from AOSP), that implements support of
AVB 2.0. This library is used for integrity checking of Android partitions
on eMMC.

libavb was added as it is and minimal changes were introduced to reduce
maintenance cost, because it will be deviated from AOSP upstream in the future.

Changes:
- license headers changed to conform SPDX-style
- avb_crc32.c dropped
- updates in avb_sysdeps_posix.c/avb_sysdeps.h

For additional details check [1] AVB 2.0 README.

[1] https://android.googlesource.com/platform/external/avb/+/master/README.md

Signed-off-by: Igor Opaniuk <igor.opaniuk@linaro.org>