capability.h warning fix

include/linux/capability.h:397: warning: "struct task_struct" declared inside parameter list
include/linux/capability.h:397: warning: its scope is only this definition or declaration, which is probably not what you want

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/capability.h

@@ -16,6 +16,8 @@
 #include <linux/types.h>
 #include <linux/compiler.h>
 
+struct task_struct;
+
 /* User-level do most of the mapping between kernel and user
    capabilities based on the version tag given by the kernel. The
    kernel might be somewhat backwards compatible, but don't bet on