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/[e-mail]-3990X/
Link: https://lore.kernel.org/all/[e-mail]/
Signed-off-by: Krzysztof Kozlowski <[e-mail]>
Reviewed-by: Charles Keepax <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Lee Jones <[e-mail]>

drivers/mfd/wm8994-core.c

···
 	wm8994->dev = &i2c->dev;
 	wm8994->irq = i2c->irq;
 
-	wm8994->type = (enum wm8994_type)i2c_get_match_data(i2c);
+	wm8994->type = (kernel_ulong_t)i2c_get_match_data(i2c);
 
 	wm8994->regmap = devm_regmap_init_i2c(i2c, &wm8994_base_regmap_config);
 	if (IS_ERR(wm8994->regmap)) {