ASoC: core: Fix volsw_range funcs so SOC_DOUBLE_R_RANGE_TLV works.

This fixes a bug when using the SOC_DOUBLE_R_RANGE_TLV macro in
the invert mode. In the non-invert case, e.g.

SOC_DOUBLE_R_RANGE_TLV("<name>", <reg_l>, <reg_r>,
					0, 40, 255, 0, <tlv>)

the range sent to the hardware is 40..255, but in the invert case:

SOC_DOUBLE_R_RANGE_TLV("<name>", <reg_l>, <reg_r>,
					0, 40, 255, 1, <tlv>)

the range 215..0 was being sent to the hardware. This commit
corrects this to 255..40 so it is consistent with the non-invert
case.

Signed-off-by: Howard Mitchell <hm@hmbedded.co.uk>
Signed-off-by: Mark Brown <broonie@kernel.org>