ASoC: mediatek: mt8365: include linux/bitfield.h

On x86, the header is not already included implicitly,
breaking compile-testing:

In file included from sound/soc/mediatek/mt8365/mt8365-afe-common.h:19,
                 from sound/soc/mediatek/mt8365/mt8365-afe-pcm.c:18:
sound/soc/mediatek/mt8365/mt8365-afe-pcm.c: In function 'mt8365_afe_cm2_mux_conn':
sound/soc/mediatek/mt8365/mt8365-reg.h:952:41: error: implicit declaration of function 'FIELD_PREP' [-Wimplicit-function-declaration]
  952 | #define CM2_AFE_CM2_CONN_CFG1(x)        FIELD_PREP(CM2_AFE_CM2_CONN_CFG1_MASK, (x))
      |                                         ^~~~~~~~~~

Included it ahead of the field definitions.

Fixes: 38c7c9dd ("ASoC: mediatek: mt8365: Add common header")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Link: https://patch.msgid.link/20240908221754.2210857-1-arnd@kernel.orgSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/mediatek/mt8365/mt8365-reg.h

@@ -10,6 +10,8 @@
 #ifndef _MT8365_REG_H_
 #define _MT8365_REG_H_
 
+#include <linux/bitfield.h>
+
 #define AUDIO_TOP_CON0			(0x0000)
 #define AUDIO_TOP_CON1			(0x0004)
 #define AUDIO_TOP_CON2			(0x0008)