Revert "ANDROID: x86: boot: Makefile: pass CLANG_FLAGS to Kbuild"

This reverts commit 3578eb5f.

This patch was not needed to fix the build up, it was a linker issue,
not a CLANG_FLAGS issue, so drop this patch.

Cc: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I18225686fcc1ae9d69230f55772b1a34f5d15e1d