MIPS: Octeon: Define ARCH_HAS_USABLE_BUILTIN_POPCOUNT for OCTEON.

OCTEON implements __builtin_popcount with a single instruction, so lets use it.
Signed-off-by: NDavid Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Cc: David Daney <ddaney@caviumnetworks.com>
Patchwork: https://patchwork.linux-mips.org/patch/1431/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/mach-cavium-octeon/cpu-feature-overrides.h

@@ -77,6 +77,14 @@ static inline int read_current_timer(unsigned long *result)
 	return 0;
 }
 
+#ifdef __OCTEON__
+/*
+ * All gcc versions that have OCTEON support define __OCTEON__ and have the
+ *  __builtin_popcount support.
+ */
+#define ARCH_HAS_USABLE_BUILTIN_POPCOUNT 1
+#endif
+
 static inline int octeon_has_saa(void)
 {
 	int id;