fix(corstone1000): include platform header file

Include platform.h file in order to remove following compiler errors,
as some warnings are being treated as errors now.
error: implicit declaration of function
'plat_core_pos_by_mpidr'[-Wimplicit-function-declaration]

Change-Id: Ie223e11e138ec9b0eef7342f450b90b215a49b15
Signed-off-by: Harsimran Singh Tungal <harsimransingh.tungal@arm.com>
1 file changed