MIPS: mm: Fix definition of R6 cache instruction

Commit a168b8f1 ("MIPS: mm: Add MIPS R6 instruction encodings") added
an incorrect definition of the redefined MIPSr6 cache instruction.

Executing any kernel code including this instuction results in a
reserved instruction exception and kernel panic.

Fix the instruction definition.

Fixes: a168b8f1Signed-off-by: NMatt Redfearn <matt.redfearn@imgtec.com>
Cc: <stable@vger.kernel.org> # 4.x-
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13663/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

arch/mips/mm/uasm-mips.c

@@ -65,7 +65,7 @@ static struct insn insn_table[] = {
 #ifndef CONFIG_CPU_MIPSR6
 	{ insn_cache,  M(cache_op, 0, 0, 0, 0, 0),  RS | RT | SIMM },
 #else
-	{ insn_cache,  M6(cache_op, 0, 0, 0, cache6_op),  RS | RT | SIMM9 },
+	{ insn_cache,  M6(spec3_op, 0, 0, 0, cache6_op),  RS | RT | SIMM9 },
 #endif
 	{ insn_daddiu, M(daddiu_op, 0, 0, 0, 0, 0), RS | RT | SIMM },
 	{ insn_daddu, M(spec_op, 0, 0, 0, 0, daddu_op), RS | RT | RD },