Identify a CHD as a PS1 disc by its volume descriptor, not by being a CD's

chdman createcd makes CD CHDs of PSP discs too, which were taken for PS1 games. A CHD is now a PS1
disc only when its volume descriptor's system ID is PLAYSTATION, and otherwise goes on to the PSP
disc checks.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

Core/Loaders.cpp

@@ -109,8 +109,7 @@ IdentifiedFileType Identify_File(FileLoader *fileLoader, std::string *errorStrin
 		return IdentifiedFileType::ERROR_IDENTIFYING;
 	}
 
-	if (extension == ".chd" && IsCDChd(fileLoader)) {
-		// PSP discs are DVDs, so a CD is a PS1 disc.
+	if (extension == ".chd" && IsPS1Chd(fileLoader)) {
 		return IdentifiedFileType::PSX_ISO;
 	}