Merge pull request #1784 from antonio-nino-diaz-arm/an/includes-arm

plat/arm: Cleanup of includes and drivers

plat/arm: scpi: Move to drivers/ folder

Change-Id: Icc59cdaf2b56f6936e9847f1894594c671db2e94
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>