pch_uart: Add uart device to irq name

This will additionally show the specific UART device instead of the
general module name. This cames in handy so check for the interupts of
a specific device if there are several of them.

Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>