net/smc: consolidate unlocking in same function

Static code checkers warn of inconsistent returns because the lgr mutex
is locked in one function and unlocked in a function called by the
locking function:
net/smc/af_smc.c:823 smc_connect_rdma() warn: inconsistent returns 'smc_client_lgr_pending'.
net/smc/af_smc.c:897 smc_connect_ism() warn: inconsistent returns 'smc_server_lgr_pending'.

Make the code consistent by doing the unlock in the same function that
fetches the lock. No functional changes.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>