staging: rts5208: remove unused xd_check_err_code function

clang with W=1 reports
drivers/staging/rts5208/xd.c:34:19: error: unused function
'xd_check_err_code' [-Werror,-Wunused-function]
static inline int xd_check_err_code(struct rtsx_chip *chip, u8 err_code)
^
This function is not used, so remove it.

Signed-off-by: Tom Rix <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/rts5208/xd.c

···
 	xd_card->err_code = err_code;
 }
 
-static inline int xd_check_err_code(struct rtsx_chip *chip, u8 err_code)
-{
-	struct xd_info *xd_card = &chip->xd_card;
-
-	return (xd_card->err_code == err_code);
-}
-
 static int xd_set_init_para(struct rtsx_chip *chip)
 {
 	struct xd_info *xd_card = &chip->xd_card;