Control type added for cases where a specific range of values
within a register are required for control.

Added convenience macros:

SOC_SINGLE_RANGE
SOC_SINGLE_RANGE_TLV

Added accessor implementations:

snd_soc_info_volsw_range
snd_soc_put_volsw_range
snd_soc_get_volsw_range
Signed-off-by: NMichal Hajduk <Michal.Hajduk@diasemi.com>
Signed-off-by: NAdam Thomson <Adam.Thomson@diasemi.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>