mmc: sdhci: Fix the timeout check window for clock and reset

We observed some premature timeouts on a virtualization platform,
the log is like this:

case 1:
[159525.255629] mmc1: Internal clock never stabilised.
[159525.255818] mmc1: sdhci: ============ SDHCI REGISTER DUMP ===========
[159525.256049] mmc1: sdhci: Sys addr:  0x00000000 | Version:  0x00001002
...
[159525.257205] mmc1: sdhci: Wake-up:   0x00000000 | Clock:    0x0000fa03
From the clock control register dump, we are pretty sure the clock was
stablized.

case 2:
[  914.550127] mmc1: Reset 0x2 never completed.
[  914.550321] mmc1: sdhci: ============ SDHCI REGISTER DUMP ===========
[  914.550608] mmc1: sdhci: Sys addr:  0x00000010 | Version:  0x00001002

After checking the sdhci code, we found the timeout check actually
has a little window that the CPU can be scheduled out and when it
comes back, the original time set or check is not valid.

Change-Id: I291379e640d2896cfdebbe73133329a64c57d8c7
Fixes: 5a436cc0 ("mmc: sdhci: Optimize delay loops")
Cc: stable@vger.kernel.org      # v4.12+
Signed-off-by: Alek Du <alek.du@intel.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Git-commit: b704441e38f645dcfba1348ca3cc1ba43d1a9f31
Git-repo: https://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc.git


Signed-off-by: Ram Prakash Gupta <rampraka@codeaurora.org>