MFC: r321589

MFC: r321589

- Check the slot type capability, set SDHCI_SLOT_{EMBEDDED,NON_REMOVABLE}
  for embedded slots. Fail in the sdhci(4) initialization for slot type
  shared, which is completely unsupported by this driver at the moment. [1]
  For Intel eMMC controllers, taking the embedded slot type into account
  obsoltes setting SDHCI_QUIRK_ALL_SLOTS_NON_REMOVABLE so remove these quirk
  entries.
- Hide the 1.8 V VDD capability when the slot is detected as non-embedded,
  as the SDHCI specification explicitly states that 1.8 V VDD is applicable
  to embedded slots only. [2]
- Define some easy bits of the SDHCI specification v4.20. [3]
- Don't leak bus_dma(9) resources in failure paths of sdhci_init_slot().

Obtained from:	DragonFlyBSD 65704a46 [1], 7ba10b88 [2], 0df14648 [3]

git-svn-id: svn://svn.freebsd.org/base/stable/10@322122 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f