tty/serial: fix ifx6x60.c declaration warning

Fix gcc warning of mixed data/code:

drivers/tty/serial/ifx6x60.c:516:2: warning: ISO C90 forbids mixed declarations and code

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Russ Gorby <russ.gorby@intel.com>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>