drm/radeon: fix firmware info version checks

BugLink: http://bugs.launchpad.net/bugs/1615620

commit 3edc38a0 upstream.

Some of the checks didn't handle frev 2 tables properly.
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

drivers/gpu/drm/radeon/radeon_atombios.c

@@ -1155,7 +1155,7 @@ bool radeon_atom_get_clock_info(struct drm_device *dev)
 		    le16_to_cpu(firmware_info->info.usReferenceClock);
 		p1pll->reference_div = 0;
 
-		if (crev < 2)
+		if ((frev < 2) && (crev < 2))
 			p1pll->pll_out_min =
 				le16_to_cpu(firmware_info->info.usMinPixelClockPLL_Output);
 		else
@@ -1164,7 +1164,7 @@ bool radeon_atom_get_clock_info(struct drm_device *dev)
 		p1pll->pll_out_max =
 		    le32_to_cpu(firmware_info->info.ulMaxPixelClockPLL_Output);
 
-		if (crev >= 4) {
+		if (((frev < 2) && (crev >= 4)) || (frev >= 2)) {
 			p1pll->lcd_pll_out_min =
 				le16_to_cpu(firmware_info->info_14.usLcdMinPixelClockPLL_Output) * 100;
 			if (p1pll->lcd_pll_out_min == 0)