drivers: tty: Mark the functions as static in n_gsm.c
drivers: tty: Mark the functions as static in n_gsm.c

Marks the functions gsm_cleanup_mux(), gsm_activate_mux(),
gsm_free_mux(), gsm_alloc_mux() and gsm_change_mtu() as static in
n_gsm.c because they are not used outside this file.

Also, drop the EXPORT_SYMBOL_GPL for the above mentioned functions
because nothing else in the kernel calls them.

This eliminates the following warnings in n_gsm.c:
drivers/tty/n_gsm.c:2022:6: warning: no previous prototype for ‘gsm_cleanup_mux’ [-Wmissing-prototypes]
drivers/tty/n_gsm.c:2076:5: warning: no previous prototype for ‘gsm_activate_mux’ [-Wmissing-prototypes]
drivers/tty/n_gsm.c:2120:6: warning: no previous prototype for ‘gsm_free_mux’ [-Wmissing-prototypes]
drivers/tty/n_gsm.c:2156:17: warning: no previous prototype for ‘gsm_alloc_mux’ [-Wmissing-prototypes]
drivers/tty/n_gsm.c:2714:5: warning: no previous prototype for ‘gsm_change_mtu’ [-Wmissing-prototypes]

Signed-off-by: Rashika Kheria <62a2cbd3422b0d621dafb7ceeff40187aeaed4ed@gmail.com>
Reviewed-by: Josh Triplett <c028c213ed5efcf30c3f4fc7361dbde0c893c5b7@joshtriplett.org>
Signed-off-by: Greg Kroah-Hartman <4645f7897fd33786a2ee1264d590b3c400559d85@linuxfoundation.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs