seccomp: Provide stub for __secure_computing()

To avoid #ifdeffery in the upcoming generic syscall entry work code provide
a stub for __secure_computing() as this is preferred over
secure_computing() because the TIF flag is already evaluated.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20200722220519.404974280@linutronix.de

include/linux/seccomp.h

@@ -61,6 +61,7 @@ struct seccomp_filter { };
 
 #ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER
 static inline int secure_computing(void) { return 0; }
+static inline int __secure_computing(void) { return 0; }
 #else
 static inline void secure_computing_strict(int this_syscall) { return; }
 #endif