x86: Optimize xstate size calculation

x86: Optimize xstate size calculation

Scan xstate IDs up to the maximum supported xstate ID.  Remove the
separate AMX xstate calculation.  Instead, exclude the AMX space from
the start of TILECFG to the end of TILEDATA in xsave_state_size.

Completed validation on SKL/SKX/SPR/SDE and compared xsave state size
with "ld.so --list-diagnostics" option, no regression.

Co-Authored-By: H.J. Lu <hjl.tools@gmail.com>
Reviewed-by: Sunil K Pandey <skpgkp2@gmail.com>