MIPS: Advertise MIPSr6 via HWCAP when appropriate

When running on a CPU implementing the release 6 of the MIPS32 or MIPS64
ISA, advertise that to userland via the appropriate HWCAP bit.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Matthew Fortune <matthew.fortune@imgtec.com>
Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-kernel@vger.kernel.org
Cc: Huacai Chen <chenhc@lemote.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/10798/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/kernel/cpu-probe.c

@@ -1524,6 +1524,9 @@ void cpu_probe(void)
 	else
 		c->srsets = 1;
 
+	if (cpu_has_mips_r6)
+		elf_hwcap |= HWCAP_MIPS_R6;
+
 	if (cpu_has_msa) {
 		c->msa_id = cpu_get_msa_id();
 		WARN(c->msa_id & MSA_IR_WRPF,