powerpc: switch to generic compat rt_sigpending()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index e43cd20..f54143c 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -146,6 +146,7 @@
 	select CLONE_BACKWARDS
 	select GENERIC_SIGALTSTACK
 	select GENERIC_COMPAT_RT_SIGPROCMASK
+	select GENERIC_COMPAT_RT_SIGPENDING
 
 config EARLY_PRINTK
 	bool