ARM: 8479/2: add implementation for arm-smccc

ARM: 8479/2: add implementation for arm-smccc

Adds implementation for arm-smccc and enables CONFIG_HAVE_SMCCC for
architectures that may support arm-smccc. It's the responsibility of the
caller to know if the SMC instruction is supported by the platform.

Reviewed-by: Lars Persson <lars.persson@axis.com>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
[egukim: Backported from mainline kernel v4.12]
Signed-off-by:eunggu kim <egukim@dignsys.com>

Change-Id: I029e75b9f2f623bf1e4c2e243537e930d96dc6cf