Fix the vrndi.s output range.

Was previously outputting only valid positive float values, but should use
a much wider range of a u32.

Might've affected randomness in some games.
jit: Actually jit vmtfc/vmfvc.

Sicne we have them and they are easy.
Initialize the VFPU revision from a PSP-3000 value.
Merge pull request #6823 from unknownbrackets/vfpu-minor

Fix the vrndi.s output range