KEYS: Include linux/errno.h in linux/verification.h

Add inclusion of linux/errno.h as otherwise the reference to EINVAL
may be invalid.

Fixes: f3cf4134c5c6 ("bpf: Add bpf_lookup_*_key() and bpf_key_put() kfuncs")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202308261414.HKw1Mrip-lkp@intel.com/
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

include/linux/verification.h

@@ -8,6 +8,7 @@
 #ifndef _LINUX_VERIFICATION_H
 #define _LINUX_VERIFICATION_H
 
+#include <linux/errno.h>
 #include <linux/types.h>
 
 /*