serial_cs: MD55x support (PCMCIA GPRS/EDGE modem) (kernel 2.6.33)

Many PCMCIA GPRS modems like: Onda Edge N100E, Novaway PC98 (OEM SPC98Z),
Rovermate Edgus Adaptmate-039 and others have same construction and
identification:

lspcmcia -vvv
Product Name:   Generic Modem: MD55x 1.00 Serial number: xxxxx-xxx
Identification: manf_id: 0x015d card_id: 0x4c45
                function: 2 (serial)
                prod_id(1): "Generic" (0xc49e4731)
                prod_id(2): "Modem: MD55x" (0x8913b110)
                prod_id(3): "1.00" (0x83dbf271)
                prod_id(4): "Serial number: xxxxx-xxx" (0x73ee9514)

Serial connection to GSM module based on Elan VPU16551 PCMCIA UART with
datasheet recommeded 14.7456MHz crystal oscillator.

By default serial_cs set UART clock == 1843200 Hz
For correct work need set clock 14745600 Hz.
This quirk already present in driver, only need add device in quirk list.

Signed-off-by: Timur Maximov <xcom.org@gmail.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>