platform/x86: acer-wmi: refactor function has_cap

Refactor function has_cap in order to avoid returning integer
values, when instead it should return booleans.

This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: "Lee, Chun-Yi" <jlee@suse.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

drivers/platform/x86/acer-wmi.c

@@ -672,10 +672,7 @@ static void __init find_quirks(void)
 
 static bool has_cap(u32 cap)
 {
-	if ((interface->capability & cap) != 0)
-		return 1;
-
-	return 0;
+	return interface->capability & cap;
 }
 
 /*