mmc: core: Donot fall back to lower speed modes for tuning errors

CRC errors are expected during tuning. MMC driver tries to fallback
to lower speed mode if it encounters consecutive CRC errors.
It should ignore CRC errors observed during tuning and shouldn't
try to fallback.

There is a check present for ignoring CRC errors for SD card
tuning commands. A new check has been added to ignore CRC errors
for eMMC tuning command as well.

Change-Id: Ic2bfa4f6a883fe30fdee85cf2e26779f3e906824
Signed-off-by: Pradeep P V K <ppvk@codeaurora.org>