hwmon: (nct6683) remove useless function

Fix the following clang warning:

drivers/hwmon/nct6683.c:491:19: warning: unused function 'in_to_reg'
[-Wunused-function].

Reported-by: Abaci Robot <[e-mail]>
Signed-off-by: Jiapeng Chong <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Guenter Roeck <[e-mail]>

drivers/hwmon/nct6683.c

···
 	return reg * scale;
 }
 
-static inline u16 in_to_reg(u32 val, u8 src)
-{
-	int scale = 16;
-
-	if (src == MON_SRC_VCC || src == MON_SRC_VSB || src == MON_SRC_AVSB ||
-	    src == MON_SRC_VBAT)
-		scale <<= 1;
-
-	return clamp_val(DIV_ROUND_CLOSEST(val, scale), 0, 127);
-}
-
 static u16 nct6683_read(struct nct6683_data *data, u16 reg)
 {
 	int res;