mmc: fsl_esdhc: add ADMA2 support

Newer eSDHC controllers support ADMA2 descriptor tables which support
64bit DMA addresses. One notable user of addresses in the upper memory
segment is the EFI loader.

If support is enabled, but the controller doesn't support ADMA2, we
will fall back to SDMA (and thus 32 bit DMA addresses only).

Signed-off-by: Michael Walle <michael@walle.cc>
diff --git a/drivers/mmc/Kconfig b/drivers/mmc/Kconfig
index 88582db..14d7913 100644
--- a/drivers/mmc/Kconfig
+++ b/drivers/mmc/Kconfig
@@ -755,6 +755,14 @@
 	  This selects support for the eSDHC (Enhanced Secure Digital Host
 	  Controller) found on numerous Freescale/NXP SoCs.
 
+config FSL_ESDHC_SUPPORT_ADMA2
+	bool "enable ADMA2 support"
+	depends on FSL_ESDHC
+	select MMC_SDHCI_ADMA_HELPERS
+	help
+	  This enables support for the ADMA2 transfer mode. If supported by the
+	  eSDHC it will allow 64bit DMA addresses.
+
 config FSL_ESDHC_33V_IO_RELIABILITY_WORKAROUND
 	bool "enable eSDHC workaround for 3.3v IO reliability issue"
 	depends on FSL_ESDHC && DM_MMC