[media] em28xx: fix I2S audio sample rate definitions and info output

The audio configuration in chip config register 0x00 and eeprom are always
consistent. But currently the audio configuration #defines for the chip config
register say 0x20 means 3 sample rates and 0x30 5 sample rates, while the eeprom
info output says 0x20 means 1 sample rate and 0x30 3 sample rates.

I've checked the datasheet excerpts I have and it seems that the meaning of
these bits is different for em2820/40 (1 and 3 sample rates) and em2860+
(3 and 5 smaple rates).
I have also checked my Hauppauge WinTV USB 2 (em2840) and the chip/eeprom
audio config 0x20 matches the sample rates reproted by the USB device
descriptor (32k only).

Signed-off-by: Frank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>