Input: cyttsp - fix memcpy size param

memcpy param is wrong because of offset in bl_cmd, this may corrupt the
stack which may cause a crash.

Tested-by: Ferruh Yigit <[e-mail]> on TMA300-DVK
Signed-off-by: Ferruh Yigit <[e-mail]>
Acked-by: Javier Martinez Canillas <[e-mail]>
Cc: [e-mail]
Signed-off-by: Dmitry Torokhov <[e-mail]>

drivers/input/touchscreen/cyttsp_core.c

···
 	memcpy(bl_cmd, bl_command, sizeof(bl_command));
 	if (ts->pdata->bl_keys)
 		memcpy(&bl_cmd[sizeof(bl_command) - CY_NUM_BL_KEYS],
-			ts->pdata->bl_keys, sizeof(bl_command));
+			ts->pdata->bl_keys, CY_NUM_BL_KEYS);
 
 	error = ttsp_write_block_data(ts, CY_REG_BASE,
 				      sizeof(bl_cmd), bl_cmd);