fix(tools/clang-tidy): ignore header include check

Newer version of clang-tidy has checks for header files inclusion
and complains if the header file needed is not directly included in the
.c file. TF-RMM does not implement this and hence ignore this check.

Change-Id: Ifa241b930305239d0fe9d26139163aa2c667aeb1
Signed-off-by: Soby Mathew <soby.mathew@arm.com>