Fixed delay 200us is not working in certain platforms. Change to
poll for reset completion status to have more reliable reset process.

Controller will set the rst_comp bit in intr_status register after
controller has completed its reset and initialization process.
Tested-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NRadu Bacrau <radu.bacrau@intel.com>
Signed-off-by: NLey Foon Tan <ley.foon.tan@intel.com>
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>