cfg80211: errno.h: define ERFKILL

Commit 1f87f7d3 (cfg80211: add rfkill support) added ERFKILL
to asm-generic/errno.h, but alpha, mips, parisc and sparc use
their own numbering scheme and do not include asm-generic/errno.h.
We need to add definition of ERFKILL for them.

Signed-off-by: Alexander Beregalov <a.beregalov@gmail.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Kyle McMartin <kyle@mcmartin.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/parisc/include/asm/errno.h b/arch/parisc/include/asm/errno.h
index e2f3ddc..9992abd 100644
--- a/arch/parisc/include/asm/errno.h
+++ b/arch/parisc/include/asm/errno.h
@@ -120,5 +120,6 @@
 #define EOWNERDEAD	254	/* Owner died */
 #define ENOTRECOVERABLE	255	/* State not recoverable */
 
+#define	ERFKILL		256	/* Operation not possible due to RF-kill */
 
 #endif