mfd: wm8994: Fix Wvoid-pointer-to-enum-cast warning (again)

mfd: wm8994: Fix Wvoid-pointer-to-enum-cast warning (again)

'type' is an enum, thus cast of pointer on 64-bit compile test with
clang and W=1 causes:

  wm8994-core.c:625:17: error: cast to smaller integer type 'enum wm8994_type' from 'const void *' [-Werror,-Wvoid-pointer-to-enum-cast]

Year ago this was solved, although LKML discussion suggested warning is
not suitable for kernel.  Nothing changed in this regard for a year, so
assume the warning will stay and we want to have warnings-free builds.

Link: https://lore.kernel.org/all/20230814160457.GA2836@dev-arch.thelio-3990X/
Link: https://lore.kernel.org/all/20230810095849.123321-1-krzysztof.kozlowski@linaro.org/
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20240606143648.152668-3-krzysztof.kozlowski@linaro.org
Signed-off-by: Lee Jones <lee@kernel.org>