Port initial UHS-1 support from FreeBSD (Only DDR52 for eMMC so far).

Port initial UHS-1 support from FreeBSD (Only DDR52 for eMMC so far).

* Fix typo from FreeBSD commit:
  SDHCI_CTRL2_DRIVER_TYPE_A/_C_D vs. SDHCI_CAN_DRIVE_TYPE_A/_C/_D.
  And these Driver Type capability bits are in the CAPABILITIES2 register.

* Hide 1.8V VDD capability when the slot is detected as a removable card
  slot, as the spec explicitly states that the 1.8V VDD is only meant to
  be for embedded slots.

* This gives ca. 75 MiB/s read speed with the eMMC in my HP X2 210
  detachable with the Intel Cherry Trail eMMC controller, in DDR52 mode.

Taken-From: FreeBSD (svn r315598)