mmc: omap_hsmmc: fix timeout for cmd and data soft reset

With HSMMC_HAS_UPDATED_RESET reset of cmd/data (SRC/SRD) can be to
quick and can be missed resulting in wait for software timeout.
With cpu_relax timeout can be long and unpredictable. Use udelay
instead for timeout implementation.

Reported-by: Yuzheng Ma <mayuzheng@kedacom.com>
Tested-by: Yuzheng Ma <mayuzheng@kedacom.com>
Reviewed-by: Hein Tibosch <hein_tibosch@yahoo.es>
Signed-off-by: Jianpeng Ma <majianpeng@gmail.com>
Signed-off-by: Balaji T K <balajitk@ti.com>
Signed-off-by: Chris Ball <cjb@laptop.org>