[ARM] arm32ve: Introduce low-level processor specific initialization

For arm32ve port (just like arm32 port), we need low-level processor
specific initialization routine which run on all cores of SMP host
and where we can implement processor specific quirks/work-arounds.

As per above, this patch adds cpu_proc.S for arm32ve which defines
proc_setup() routine for processor specific initialization.

This patch also fixes SMP initialization for Cortex-A15. On Cortex-A15
based SMP host we need to set ACTLR.SMP bit at boot time on all cores.
This will enable a Cortex-A15 core to receive instruction cache, BTB,
and TLB maintenance operations from other Cortex-A15 cores.
(Please refer page 125 of DDI0438C_cortex_a15_r2p0_trm.pdf)

Cc: Po-wen Cheng <sting.cheng@gmail.com>
Reported-by: Po-wen Cheng <sting.cheng@gmail.com>
Signed-off-by: Anup Patel <anup@brainfault.org>