RDMA/core: Fix repeated words in comments

Corrected the repeated words in the documentation of
rdma_replace_ah_attr() and ib_resolve_unicast_gid_dmac()
functions.

Signed-off-by: Rohit Chavan <roheetchavan@gmail.com>
Link: https://lore.kernel.org/r/20230824081304.408-1-roheetchavan@gmail.com


Signed-off-by: Leon Romanovsky <leon@kernel.org>