fix(versal-net): use api_id directly without FUNCID_MASK

The purpose of this code is to extract api_id from smc_fid but this masking
is done already in the code with using generic mask from smccc.h
(FUNCID_NUM_MASK). That's why remove FUNCID_MASK is which not needed and
actually also equal to already used FUNCID_NUM_MASK.

Signed-off-by: Michal Simek <michal.simek@amd.com>
Change-Id: I1113825baa5d9d58d9d7c5d9d5855fecf62e8d45