path_util: Resolve `-Wpointer-bool-conversion` warning

Clang (rightfully) warns that we are checking for the existence of
pointer to something just allocated on the stack, which is always true.

Instead, check whether GetModuleFileNameW failed.

Co-authored-by: Mai M <mathew1800@gmail.com>

src/common/fs/path_util.cpp

@@ -232,9 +232,7 @@ void SetYuzuPath(YuzuPath yuzu_path, const fs::path& new_path) {
 fs::path GetExeDirectory() {
     wchar_t exe_path[MAX_PATH];
 
-    GetModuleFileNameW(nullptr, exe_path, MAX_PATH);
-
-    if (!exe_path) {
+    if (GetModuleFileNameW(nullptr, exe_path, MAX_PATH) == 0) {
         LOG_ERROR(Common_Filesystem,
                   "Failed to get the path to the executable of the current process");
     }