Rockbox

Currently we have a driver-specific struct and region list for each tuner driver, which specifies settings for an FM region: FM band frequency range, frequency spacing and deemphasis. This information is mostly already present in the fm_region_data struct.

This patch updates the fm_region_data struct (adding a "deemphasis" field), allowing all of the driver-specific structs to be removed. Each tuner driver now calculates its region settings from the fields in the common fm_region_data struct instead of taking it from its own struct.
For the targets I compiled this for, there was a net binsize saving (and also source code lines savings).

Please test this on your target. I am able to test targets with LV24020, SI4700, RDA5802 tuners myself. Other drivers that need testing are TEA5760, TEA5767 and the ipod remote tuner.
Stuff to test:
* do FM channels still appear on the right frequency? (this tests FM band setting)
* do you hear a change in high frequencies when switching between the Europe and USA/Canada setting? (this test deemphasis, works only for stations where the tenths of MHz are odd). The europe setting should sound brighter.