lib: pmp_set/pmp_get moved errors from runtime to compile time

pmp_set/pmp_get calculates the location of the CSR register separately
through conditional compilation. In the case of non-32-bit and 64-bit,
we can report an error directly through #error without putting it at
runtime

Signed-off-by: Xiang W <wxjstz@126.com>
Reviewed-by: Anup Patel <anup@brainfault.org>