arm64: compat: map SPSR_ELx<->PSR for signals

arm64: compat: map SPSR_ELx<->PSR for signals

The SPSR_ELx format for exceptions taken from AArch32 differs from the
AArch32 PSR format. Thus, we must translate between the two when setting
up a compat sigframe, or restoring context from a compat sigframe.

Signed-off-by: Mark Rutland <[email protected]>
Fixes: 7206dc93a58fb764 ("arm64: Expose Arm v8.4 features")
Cc: Catalin Marinas <[email protected]>
Cc: Suzuki Poulose <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Will Deacon <[email protected]>