Input: edt-ft5x06 - unify the crc check

With this patch, the CRC is always verified by the same function, even in
the case of accessing registers where the number of bytes is minimal.

Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Link: https://lore.kernel.org/r/20230402200951.1032513-9-dario.binacchi@amarulasolutions.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Author: passgat

drivers/input/touchscreen/edt-ft5x06.c

@@ -240,13 +240,10 @@ static int edt_M06_i2c_read(void *context, const void *reg_buf, size_t reg_size,
 		if (!edt_ft5x06_ts_check_crc(tsdata, val_buf, val_size))
 			return -EIO;
 	} else if (reg_read) {
-		u8 crc = wbuf[0] ^ wbuf[1] ^ rbuf[0];
-
-		if (crc != rbuf[1]) {
-			dev_err(dev, "crc error: 0x%02x expected, got 0x%02x\n",
-				crc, rbuf[1]);
+		wbuf[2] = rbuf[0];
+		wbuf[3] = rbuf[1];
+		if (!edt_ft5x06_ts_check_crc(tsdata, wbuf, 4))
 			return -EIO;
-		}
 
 		*((u8 *)val_buf) = rbuf[0];
 	}