UPSTREAM: kbuild: use CONFIG_CC_VERSION_TEXT to construct LINUX_COMPILER macro

scripts/mkcompile_h runs $(CC) just for getting the version string.
Reuse CONFIG_CC_VERSION_TEXT for optimization.

For GCC, this slightly changes the version string. I do not think it
is a big deal as we do not have the defined format for LINUX_COMPILER.
In fact, the recent commit 4831f7ad ("kbuild: mkcompile_h:
Include $LD version in /proc/version") added the linker version.

Bug: 168274246

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
(cherry picked from commit 9a950154668729a472d17b8e307d92e7c60f45f7)
Signed-off-by: Mars Lin <marslin@google.com>
Change-Id: I66bac5b44bf764e7c0e432ae17bcdf06d79c96d0