mmc: host: renesas_sdhi: Fix the actual clock

Wrong actual clock reported, if the SD clock division ratio is other
than 1:1(bits DIV[7:0] in SD_CLK_CTRL are set to 11111111).

On high speed mode, cat /sys/kernel/debug/mmc1/ios
Without the patch:
clock: 50000000 Hz
actual clock: 200000000 Hz

After the fix:
clock: 50000000 Hz
actual clock: 50000000 Hz

Signed-off-by: Biju Das <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Ulf Hansson <[e-mail]>

drivers/mmc/host/renesas_sdhi_core.c

···
 			clk &= ~0xff;
 	}
 
-	sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, clk & CLK_CTL_DIV_MASK);
+	clock = clk & CLK_CTL_DIV_MASK;
+	if (clock != 0xff)
+		host->mmc->actual_clock /= (1 << (ffs(clock) + 1));
+
+	sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, clock);
 	if (!(host->pdata->flags & TMIO_MMC_MIN_RCAR2))
 		usleep_range(10000, 11000);