Input: hynitron_cstxxx - initialize tmp to 0 to fix uninitialized variable issue

In the very unlikely event the cst3xx_i2c_write() fails inside of the
cst3xx_bootloader_enter() function 5 times in a row, the uninitalized
value of tmp will get compared to CST3XX_BOOTLDR_CHK_VAL. Initialize
the value of tmp to 0 so that in this unlikely event we are comparing
0 instead of an uninitalized variable.

Fixes: 66603243 ("Input: add driver for Hynitron cstxxx touchscreens")
Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
Reported-by: Dan Carpenter <error27@gmail.com>
Link: https://lore.kernel.org/r/20221117195921.2291-1-macroalpha82@gmail.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/touchscreen/hynitron_cstxxx.c

@@ -210,7 +210,7 @@ static int cst3xx_bootloader_enter(struct i2c_client *client)
 {
 	int err;
 	u8 retry;
-	u32 tmp;
+	u32 tmp = 0;
 	unsigned char buf[3];
 
 	for (retry = 0; retry < 5; retry++) {