staging: rtl8723bs: remove unused variable 'start' in hal/sdio_halinit.c

fix following W=1 compiler issue:

drivers/staging/rtl8723bs/hal/sdio_halinit.c:
In function '_ReadAdapterInfo8723BS':
drivers/staging/rtl8723bs/hal/sdio_halinit.c:1156:16:
warning: variable 'start' set but not used [-Wunused-but-set-variable]
1156 | unsigned long start;
| ^~~~~

Signed-off-by: Fabio Aiuto <[e-mail]>
Link: https://lore.kernel.org/r/ce1f[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/rtl8723bs/hal/sdio_halinit.c

···
 static s32 _ReadAdapterInfo8723BS(struct adapter *padapter)
 {
 	u8 val8;
-	unsigned long start;
 
 	/*  before access eFuse, make sure card enable has been called */
 	if (!padapter->hw_init_completed)
···
 	val8 = rtw_read8(padapter, 0x4e);
 	val8 |= BIT(6);
 	rtw_write8(padapter, 0x4e, val8);
-
-
-	start = jiffies;
 
 	_EfuseCellSel(padapter);
 	_ReadRFType(padapter);