serial: samsung: correct the case and default order in switch

The cases should comes before default in a switch.

Even if we want the case and default to share same code.
Its good to define the case first followed by default.

Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>