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

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: 66603243f528 ("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.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>