[syscalls] Add ARM SMCCC support to SMC syscall

In order to support the full range of services that are available via
the ARM Secure Monitor, zx_smc_call needed to gain some additional input
and output parameters. These additional parameters bring the syscall in
line with the ARM SMC Calling Convention where there are eight input
registers and four output registers.

The SMC invocation itself was moved out from underneath the PSCI kernel
driver to the arm64 arch specific component. All current SMC invocations
were updated to the new function and there are currently no calls from
higher layers.

Change-Id: I5577479a7f960a85a04cc6d978c27a2e37246a2f