MIPS: Move generated code to .text for microMIPS

MIPS: Move generated code to .text for microMIPS

Prepare of a next patch which will call tlbmiss_handler_setup_pgd on
microMIPS. MicroMIPS complains if the called code s not in the .text
section. To fix this we generate code into space reserved in
arch/mips/mm/tlb-funcs.S

While there, move the rest of the generated functions (handle_tlbl,
handle_tlbs, handle_tlbm) to the same file.

Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5542/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>