MAINTAINERS: adjust entry after renaming parisc serial driver

Commit 9e4e2ce1 ("parisc/serial: Rename 8250_gsc.c to 8250_parisc.c")
renames the parisc serial driver file, but does not adjust the entry in
MAINTAINERS.

Hence, ./scripts/get_maintainer.pl --self-test=patterns complains about a
broken reference.

Repair this file reference in PARISC ARCHITECTURE.
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Fixes: 9e4e2ce1 ("parisc/serial: Rename 8250_gsc.c to 8250_parisc.c")
Signed-off-by: Helge Deller <deller@gmx.de>

MAINTAINERS

@@ -15617,7 +15617,7 @@ F:	drivers/input/serio/gscps2.c
 F:	drivers/input/serio/hp_sdc*
 F:	drivers/parisc/
 F:	drivers/parport/parport_gsc.*
-F:	drivers/tty/serial/8250/8250_gsc.c
+F:	drivers/tty/serial/8250/8250_parisc.c
 F:	drivers/video/console/sti*
 F:	drivers/video/fbdev/sti*
 F:	drivers/video/logo/logo_parisc*