refactor(ffa_helpers): use bitfields for memory access bitmaps

Instead of doing the bit-manipulation manually, these types can be
declared as structs where the fields are given explicit bitwidths. The
compiler will generate the appropriate bit-manipulation automatically.

Change-Id: I0d4754466b1e70d1b36cb039bfe9e7701ebbd60f
Signed-off-by: Karl Meakin <karl.meakin@arm.com>
3 files changed