ASoC: max98090: Simplify max98090_readable_register implementation

The readable registers are in consecutive ranges:
	0x01 ~ 0x03, 0x0D ~ 0xD1, 0xFF
So simplify the implementation by specifying a range of consecutive values
in a single case label.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Reviewed-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>