tgt: Drop dependency against KERNEL_DIRECT_IO

This was removed in LEDE commit 0b7ed65cec
("kernel: remove out of tree direct-io disable hack")

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>

net/tgt/Makefile

@@ -30,7 +30,7 @@ define Package/tgt
   CATEGORY:=Network
   URL:=http://stgt.sourceforge.net/
   TITLE:=userspace iSCSI target
-  DEPENDS:=+libpthread +libaio @KERNEL_AIO @KERNEL_DIRECT_IO
+  DEPENDS:=+libpthread +libaio @KERNEL_AIO
 endef
 
 define Package/tgt/description