[NET]: Correct dev_alloc_skb kerneldoc

dev_alloc_skb is designated for RX descriptors, not TX. (Some drivers
use it for the latter anyway, but that's a different story)

Signed-off-by: Christoph Hellwig <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/linux/skbuff.h

···
 }
 
 /**
- *	__dev_alloc_skb - allocate an skbuff for sending
+ *	__dev_alloc_skb - allocate an skbuff for receiving
  *	@length: length to allocate
  *	@gfp_mask: get_free_pages mask, passed to alloc_skb
  *
···
 }
 
 /**
- *	dev_alloc_skb - allocate an skbuff for sending
+ *	dev_alloc_skb - allocate an skbuff for receiving
  *	@length: length to allocate
  *
  *	Allocate a new &sk_buff and assign it a usage count of one. The