mmc: core: Fix the timing related checks in partial_init

If the card (which is a eMMC 5.1 complaint card) is scaled down
to HS200, then the current logic in partial_init doesn't invoke
tuning due to these invalid checks.

Change-Id: I1e5cbb6a2dfff129acdb27e27ea090d58197f41c
Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>