sparc: sigutil: Include <linux/errno.h>

This file introduced in 2.6.32.47 currently fails to compile:

arch/sparc/kernel/sigutil_64.c: In function 'save_fpu_state':
arch/sparc/kernel/sigutil_64.c:25: error: 'EFAULT' undeclared (first use in this function)
Signed-off-by: NBen Hutchings <ben@decadent.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

arch/sparc/kernel/sigutil_64.c

@@ -2,6 +2,7 @@
 #include <linux/types.h>
 #include <linux/thread_info.h>
 #include <linux/uaccess.h>
+#include <linux/errno.h>
 
 #include <asm/sigcontext.h>
 #include <asm/fpumacro.h>