Blackfin: add new cacheflush syscall

Flushing caches sometimes requires anomaly workarounds which require
supervisor-only insns.  Normally we don't need to flush caches from
userspace so this isn't a problem, but when gcc generates trampolines
on the stack, we do.

So add a new syscall for gcc to use modeled after the mips version.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/arch/blackfin/mach-common/entry.S b/arch/blackfin/mach-common/entry.S
index 16ea779..2ca915e 100644
--- a/arch/blackfin/mach-common/entry.S
+++ b/arch/blackfin/mach-common/entry.S
@@ -1737,6 +1737,7 @@
 	.long _sys_fanotify_init
 	.long _sys_fanotify_mark
 	.long _sys_prlimit64
+	.long _sys_cacheflush
 
 	.rept NR_syscalls-(.-_sys_call_table)/4
 	.long _sys_ni_syscall