MIPS: Use dedicated exception handler if CPU supports RI/XI exceptions

MIPS: Use dedicated exception handler if CPU supports RI/XI exceptions

Use the regular tlb_do_page_fault_0 (no write) handler to handle
the RI and XI exceptions. Also skip the RI/XI validation check
on TLB load handler since it's redundant when the CPU has
unique RI/XI exceptions.

Singed-off-by: Leonid Yegoshin <[email protected]>
Signed-off-by: Markos Chandras <[email protected]>
Cc: [email protected]
Patchwork: https://patchwork.linux-mips.org/patch/7339/
Signed-off-by: Ralf Baechle <[email protected]>