RISC-V: Ensure vtype for full-register moves [PR117544].
As discussed in PR117544 the VTYPE register is not preserved across
function calls. Even though vmv1r-like instructions operate
independently of the actual vtype they still require a valid vtype. As
we cannot guarantee that the vtype is valid we must make sure to emit a
vsetvl between a function call and a vmv1r.v.
This patch makes the necessary changes by splitting the full-reg-move
insns into patterns that use the vtype register and adding vmov to the
types of instructions requiring a vset.