pmf: Make the runtime instrumentation work on AArch32

Ported the pmf asm macros and the asm code in the bl31 entrypoint
necessary for the instrumentation to AArch32.

Since smc dispatch is handled by the bl32 payload on AArch32, we
provide this service only if AARCH32_SP=sp_min is set.

Signed-off-by: Bence Szépkúti <bence.szepkuti@arm.com>
Change-Id: Id33b7e9762ae86a4f4b40d7f1b37a90e5130c8ac