Makefile: add -ffat-lto-objects to CFLAGS
Makefile: add -ffat-lto-objects to CFLAGS

This command line option causes .o files to include additional
information and seems to be triggering a more thorough code analysis.
In particular, the uninitalized variable use cases previously missed
trigger compilation warnings when this option is enabled.

Generated code size for the Cr50 target does not change.

BRANCH=cr50, cr50-mp
BUG=b:134623681
TEST=make buildall -j

Change-Id: I1d916f0e6592757a073ae44e8e38c8a60384d576
Signed-off-by: Vadim Bendebury <5515d6d2d0829cbe0dd0dcf2094aaded06d58514@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1648924
Reviewed-by: Patrick Georgi <bc411205f21846a74924ee7b489c75617ec76078@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec