drm/amdgpu/dc: Use WARN_ON_ONCE for ASSERT

Once should generally be enough for diagnosing what lead up to it,
repeating it over and over can be pretty annoying.

Signed-off-by: Michel Dänzer <mdaenzer@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/os_types.h

@@ -108,7 +108,7 @@
 #define ASSERT(expr) ASSERT_CRITICAL(expr)
 
 #else
-#define ASSERT(expr) WARN_ON(!(expr))
+#define ASSERT(expr) WARN_ON_ONCE(!(expr))
 #endif
 
 #define BREAK_TO_DEBUGGER() ASSERT(0)