Remove the use of #ifdefs around each case statement of the chip ID
and type validation switches.

We must ensure that the contained code still compiles to nothing if
support for that codec was not built into the kernel, to prevent
creation of link references to missing functions. So the ifdefs are
replaced with a use of the IS_ENABLED() macro.
Signed-off-by: Richard Fitzgerald <rf@opensource.wolfsonmicro.com>
Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>