[cmake] Promote Qt FreeBSD (fix building with Qt 6.10.1) (#3335)

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/3335
Reviewed-by: Maufeat <sahyno1996@gmail.com>
Reviewed-by: CamilleLaVey <camillelavey99@gmail.com>
Co-authored-by: DraVee <dravee@eden-emu.dev>
Co-committed-by: DraVee <dravee@eden-emu.dev>

CMakeLists.txt

@@ -601,7 +601,7 @@ if (ENABLE_QT)
         find_package(Qt6 REQUIRED COMPONENTS Multimedia)
     endif()
 
-    if (CMAKE_SYSTEM_NAME STREQUAL "Linux")
+    if (PLATFORM_LINUX OR PLATFORM_FREEBSD)
         # yes Qt, we get it
         set(QT_NO_PRIVATE_MODULE_WARNING ON)
         find_package(Qt6 REQUIRED COMPONENTS DBus OPTIONAL_COMPONENTS GuiPrivate)