[PATCH] fmr pool: remove unnecessary pointer dereference

ib_fmr_pool_map_phys gets the virtual address by pointer but never writes
there, and users (e.g.  srp) seem to assume this and ignore the value
returned.  This patch cleans up the API to get the VA by value, and updates
all users.

Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Acked-by: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>