[XFRM]: Fix missing protocol comparison of larval SAs.

I noticed that in xfrm_state_add we look for the larval SA in a few
places without checking for protocol match. So when using both 
AH and ESP, whichever one gets added first, deletes the larval SA. 
It seems AH always gets added first and ESP is always the larval 
SA's protocol since the xfrm->tmpl has it first. Thus causing the
additional km_query()

Adding the check eliminates accidental double SA creation. 

Signed-off-by: Joy Latten <latten@austin.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>