serial167: Kill unused variables

commits 638157bc ("serial167: prepare to push
BKL down into drivers") and 4165fe4e ("tty:
Fix up char drivers request_room usage") removed code without removing the
corresponding variables:

| drivers/char/serial167.c: In function 'cd2401_rx_interrupt':
| drivers/char/serial167.c:630: warning: unused variable 'len'
| drivers/char/serial167.c: In function 'cy_ioctl':
| drivers/char/serial167.c:1531: warning: unused variable 'val'

Remove the variables to kill the warnings.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>