mac80211: build airo on x86 only

airo requires ISA_DMA_API and
that symbol is only set on some ppc,malta,x86
x86 is probably only platform where that driver is used

fixes buildbot errors on ar71xx,lantiq ...:
airo.ko is missing

Signed-off-by: Dirk Neukirchen <dirkneukirchen@web.de>

SVN-Revision: 49073

package/kernel/mac80211/Makefile

@@ -142,7 +142,7 @@ endef
 define KernelPackage/airo
   $(call KernelPackage/mac80211/Default)
   TITLE:=Cisco Aironet driver
-  DEPENDS+=@PCI_SUPPORT +@DRIVER_WEXT_SUPPORT +kmod-cfg80211
+  DEPENDS+=@PCI_SUPPORT +@DRIVER_WEXT_SUPPORT +kmod-cfg80211 @TARGET_x86
   FILES:=$(PKG_BUILD_DIR)/drivers/net/wireless/cisco/airo.ko
   AUTOLOAD:=$(call AutoProbe,airo)
 endef