SPM: Return error code when NS causes a programmer error

According to Firmware Framework 1.0 specification, a PROGRAMMER ERROR
should return error code when the caller is in the NSPE.

Change-Id: Ia47d5edc621ea1cab16b1d50eb82c2908276e7ef
Signed-off-by: Shawn Shan <Shawn.Shan@arm.com>
3 files changed