MIPS: Refactor dumping of TLB registers for r3k/r4k

The TLB registers are dumped in a couble of places:
 - sysrq_tlbdump_single() - when dumping TLB state.
 - do_mcheck() - in response to a machine check error.

The main TLB registers also differ between r3k and r4k, but r4k appears
to be assumed.

Refactor this code into a dump_tlb_regs() function, implemented for both
r3k and r4k, and used by both of the above functions.

Fixes: d1e9a4f54735 ("MIPS: Add SysRq operation to dump TLBs on all CPUs")
Suggested-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10721/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/lib/r3k_dump_tlb.c b/arch/mips/lib/r3k_dump_tlb.c
index 8e0d3cf..cfcbb52 100644
--- a/arch/mips/lib/r3k_dump_tlb.c
+++ b/arch/mips/lib/r3k_dump_tlb.c
@@ -14,6 +14,17 @@
 #include <asm/pgtable.h>
 #include <asm/tlbdebug.h>
 
+extern int r3k_have_wired_reg;
+
+void dump_tlb_regs(void)
+{
+	pr_info("Index    : %0x\n", read_c0_index());
+	pr_info("EntryHi  : %0lx\n", read_c0_entryhi());
+	pr_info("EntryLo  : %0lx\n", read_c0_entrylo0());
+	if (r3k_have_wired_reg)
+		pr_info("Wired    : %0x\n", read_c0_wired());
+}
+
 static void dump_tlb(int first, int last)
 {
 	int	i;