CPP-Check: Use Absolute Path of Toolchain File

Without a specified path, compiler would search for toolchain file in
trusted-firmware/build-cppcheck/, which is not the correct path.
Absolute path could fix the error of unable to find toolchain file.

Change-Id: I7f1c5540762fcb1862f1152351ed81cd7477c560
Signed-off-by: Xinyu Zhang <xinyu.zhang@arm.com>
1 file changed