refactor(tftf): move SIMD/FPU save/restore routine to common lib

- Move FPU routines to common lib
- FPU/SIMD state consist of the 32 SIMD vectors, FPCR and FPSR registers
- Test that FPU/SIMD state are preserved during a context switch
  between secure/non-secure.

Signed-off-by: Shruti Gupta <shruti.gupta@arm.com>
Change-Id: I88f0a9f716aafdd634c4eae5b885f839bb3deb00
10 files changed