serial: icom: make icom_acfg_baud const and unsigned

The baud rates are unsigned constants. So mark them as such.

Not only it makes sense, but they are passed also to
uart_get_baud_rate() and that expects unsigned int as baud rates on
input.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220421085808.24152-8-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/icom.c

@@ -47,7 +47,7 @@
 #define ICOM_DRIVER_NAME "icom"
 #define NR_PORTS	       128
 
-static int icom_acfg_baud[] = {
+static const unsigned int icom_acfg_baud[] = {
 	300,
 	600,
 	900,