feat(el3-spmc): add support to setup S-EL0 context

Add support to setup S-EL0 context by setting up the following

S-EL1 shim exception handlers: This is a trampoline between S-EL0 and
                               monitor running at EL3 and is used to
			       handle or forward exceptions from S-EL0.

Boot Info region: This region holds the boot protocol data that is
                  passed between SPMC and SP.

Setup system registers: Setup sctlr_el1, vbar_el1, cntkctl_el1,
                        ctx_cpacr_el1(enable fp and smid), spsr and
			sp_el0

Signed-off-by: Achin Gupta <achin.gupta@arm.com>
Signed-off-by: Nishant Sharma <nishant.sharma@arm.com>
Change-Id: I82d21fcd95529f235bee8bf838d36a2ac519bb0a
3 files changed