MIPS: Export get_c0_perfcount_int()

get_c0_perfcount_int is tested from oprofile code. If oprofile is
compiled as module, get_c0_perfcount_int needs to be exported, otherwise
it cannot be resolved.

Fixes: a669efc4a3 ("MIPS: Add hook to get C0 performance counter interrupt")
Cc: stable@vger.kernel.org # v3.19+
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: abrestic@chromium.org
Patchwork: https://patchwork.linux-mips.org/patch/10763/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/ath79/setup.c

@@ -190,6 +190,7 @@ int get_c0_perfcount_int(void)
 {
 	return ATH79_MISC_IRQ(5);
 }
+EXPORT_SYMBOL_GPL(get_c0_perfcount_int);
 
 unsigned int get_c0_compare_int(void)
 {