RDMA/sw/rdmavt/mr: Fix some issues related to formatting and missing descriptions

Fixes the following W=1 kernel build warning(s):

 drivers/infiniband/sw/rdmavt/mr.c:380: warning: Function parameter or member 'virt_addr' not described in 'rvt_reg_user_mr'
 drivers/infiniband/sw/rdmavt/mr.c:449: warning: Function parameter or member 'qp' not described in 'rvt_dereg_clean_qp_cb'
 drivers/infiniband/sw/rdmavt/mr.c:449: warning: Function parameter or member 'v' not described in 'rvt_dereg_clean_qp_cb'
 drivers/infiniband/sw/rdmavt/mr.c:466: warning: Function parameter or member 'mr' not described in 'rvt_dereg_clean_qps'
 drivers/infiniband/sw/rdmavt/mr.c:484: warning: Function parameter or member 'mr' not described in 'rvt_check_refs'
 drivers/infiniband/sw/rdmavt/mr.c:484: warning: Function parameter or member 't' not described in 'rvt_check_refs'
 drivers/infiniband/sw/rdmavt/mr.c:513: warning: Function parameter or member 'mr' not described in 'rvt_mr_has_lkey'
 drivers/infiniband/sw/rdmavt/mr.c:513: warning: Function parameter or member 'lkey' not described in 'rvt_mr_has_lkey'
 drivers/infiniband/sw/rdmavt/mr.c:526: warning: Function parameter or member 'ss' not described in 'rvt_ss_has_lkey'
 drivers/infiniband/sw/rdmavt/mr.c:526: warning: Function parameter or member 'lkey' not described in 'rvt_ss_has_lkey'
 drivers/infiniband/sw/rdmavt/mr.c:551: warning: Function parameter or member 'udata' not described in 'rvt_dereg_mr'

Link: https://lore.kernel.org/r/20210121094519.2044049-27-lee.jones@linaro.org
Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Cc: Mike Marciniszyn <mike.marciniszyn@cornelisnetworks.com>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: linux-rdma@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>