tty/serial: altera_uart: use more informative labels in /proc/interrupts

Prior to this patch:

~# cat /proc/interrupts
...
 40:        123          0     GIC-0  72 Level     altera_uart
 41:          9          0     GIC-0  73 Level     altera_uart

After this patch:

~# cat /proc/interrupts
...
 40:          6          0     GIC-0  72 Level     ff200100.fpga-uart0
 41:         28          0     GIC-0  73 Level     ff200200.fpga-uart1

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Acked-by: Tobias Klauser <tklauser@distanz.ch>
Link: https://lore.kernel.org/r/20231217195601.236002-1-antonynpavlov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>