mmc: eSDHC: Add ADMA mode support

The register of eSDHC Host Controller Capabilities is not compatible with
standard SDHC register, and eSDHC cannot support End Attribute in NOP ADMA
descriptor. With this patch eSDHC can works in ADMA mode and performance
can be improved.

Signed-off-by: Jerry Huang <Chang-Ming.Huang@freescale.com>
Signed-off-by: Pan Jiafei <Jiafei.Pan@freescale.com>
Signed-off-by: Jason Jin <Jason.jin@freescale.com>
Acked-by: Anton Vorontsov <cbouatmailru@gmail.com>
Signed-off-by: Chris Ball <cjb@laptop.org>