asus-laptop: Fix an uninitialized variable

The value returned by acpi_evaluate_integer() is not checked,
but the result is not always successful, so it is necessary to
add a check of the returned value.

If the result remains negative during three iterations of the loop,
then the uninitialized variable 'val' will be used in the clamp_val()
macro, so it must be initialized with the current value of the 'curr'
variable.

In this case, the algorithm should be less noisy.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: b23910c2194e ("asus-laptop: Pegatron Lucid accelerometer")
Cc: [e-mail]
Signed-off-by: Denis Arefev <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Reviewed-by: Ilpo Järvinen <[e-mail]>
Signed-off-by: Ilpo Järvinen <[e-mail]>

drivers/platform/x86/asus-laptop.c

···
 
 static int pega_acc_axis(struct asus_laptop *asus, int curr, char *method)
 {
+	unsigned long long val = (unsigned long long)curr;
+	acpi_status status;
 	int i, delta;
-	unsigned long long val;
-	for (i = 0; i < PEGA_ACC_RETRIES; i++) {
-		acpi_evaluate_integer(asus->handle, method, NULL, &val);
 
+	for (i = 0; i < PEGA_ACC_RETRIES; i++) {
+		status = acpi_evaluate_integer(asus->handle, method, NULL, &val);
+		if (ACPI_FAILURE(status))
+			continue;
 		/* The output is noisy.  From reading the ASL
 		 * dissassembly, timeout errors are returned with 1's
 		 * in the high word, and the lack of locking around