Convert to SPDX license tags

Signed-off-by: Gerwin Klein <gerwin.klein@data61.csiro.au>

libsel4vmmplatsupport: arm SMC handler support

Added support for handling arm vcpu exceptions related to SMC
calls. At this point, the source for handling smc related
exceptions simply provides functionality to decode a SMC
instruction. This meaning it doesn't perform anything from an
SMC instruction. However this lays the necessary infrastructure
to handle services such as PSCI.

Co-authored-by: Anna Lyons <anna@gh.st>