mmc: Change the frequency to MMC_HS_52 when selecting hs400

Per JESD84-B51 P47, host need to change frequency to <=52MHz
after setting HS_TIMING to 0x1, and host need to set the
8-bit DDR buswidth. Currently setting the frequency to 26MHz
and trying to switch 8-bit DDR buswidth resulting timeouts.

mmc dev 1 0
Select HS400 failed -110
switch to partitions #0, OK
mmc1(part 0) is current device

Signed-off-by: Venkatesh Yadav Abbarapu <venkatesh.abbarapu@amd.com>
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index 0b881f1..7e702c3 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -997,8 +997,8 @@
 	 * Extended CSD. Reconfigure the controller to run at HS mode.
 	 */
 	if (hsdowngrade) {
-		mmc_select_mode(mmc, MMC_HS);
-		mmc_set_clock(mmc, mmc_mode2freq(mmc, MMC_HS), false);
+		mmc_select_mode(mmc, MMC_HS_52);
+		mmc_set_clock(mmc, mmc_mode2freq(mmc, MMC_HS_52), false);
 	}
 #endif
 
@@ -2077,7 +2077,7 @@
 	}
 
 	/* Set back to HS */
-	mmc_set_card_speed(mmc, MMC_HS, true);
+	mmc_set_card_speed(mmc, MMC_HS_52, true);
 
 	err = mmc_hs400_prepare_ddr(mmc);
 	if (err)