drm/radeon: don't share PPLLs on DCE4.1

Sharing PPLLs seems to cause problems on some boards.

Bug:
https://bugs.freedesktop.org/show_bug.cgi?id=45334

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
diff --git a/drivers/gpu/drm/radeon/atombios_crtc.c b/drivers/gpu/drm/radeon/atombios_crtc.c
index bf87f6d..86d9ee0 100644
--- a/drivers/gpu/drm/radeon/atombios_crtc.c
+++ b/drivers/gpu/drm/radeon/atombios_crtc.c
@@ -1753,7 +1753,7 @@
 				if (pll != ATOM_PPLL_INVALID)
 					return pll;
 			}
-		} else {
+		} else if (!ASIC_IS_DCE41(rdev)) { /* Don't share PLLs on DCE4.1 chips */
 			/* use the same PPLL for all monitors with the same clock */
 			pll = radeon_get_shared_nondp_ppll(crtc);
 			if (pll != ATOM_PPLL_INVALID)