mmc: sdhci-pci: Remove MMC_CAP_BUS_WIDTH_TEST for Intel controllers

The CMD19/CMD14 bus width test has been found to be unreliable in
some cases.  It is not essential, so simply remove it.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>