ibmvnic: merge do_change_param_reset into do_reset

ibmvnic: merge do_change_param_reset into do_reset

Commit b27507bb59ed ("net/ibmvnic: unlock rtnl_lock in reset so
linkwatch_event can run") introduced do_change_param_reset function to
solve the rtnl lock issue. Majority of the code in do_change_param_reset
duplicates do_reset. Also, we can handle the rtnl lock issue in do_reset
itself. Hence merge do_change_param_reset back into do_reset to clean up
the code.

Signed-off-by: Lijun Pan <ljp@linux.ibm.com>
Link: https://lore.kernel.org/r/20201031094645.17255-1-ljp@linux.ibm.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>