serial: mvebu-uart: use driver name when requesting an interrupt

Use the driver name when requesting an interrupt for consistency.

Avoids possible confusion with DW8250 driver interrupt names in
/proc/interrupts.

Signed-off-by: Yehuda Yitschak <yehuday@marvell.com>
Signed-off-by: Miquel Raynal <miquel.raynal@free-electrons.com>
Reviewed-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>