mmc: sdhci-acpi: Tidy Intel slot probe functions into one

Tidy Intel slot probe functions into one. A single function can be used
because the logic uses hid / uid as necessary to identify devices anyway.
This gets rid of some pointless comments and checks for variables that
cannot possibly be NULL, as well as giving the function a name that
identifies it as specific to Intel controllers.

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