Kconfig: Migrate BOUNCE_BUFFER

The bounce buffer is used by a few drivers (most of the MMC drivers)
to overcome limitations in their respective DMA implementation.

This moves the configuration to Kconfig and makes it user-selectable
(even though it will be a required feature to make those drivers
work): the expected usage is for drivers depending on this to 'select'
it unconditionally from their respective Kconfig (see follow-up
patches).

This commit includes a full migration using moveconfig.py to ensure
that each commit compiles.  To ensure bisectability we update
dependencies of various drivers to now select BOUNCE_BUFFER when needed.

[trini: Squash all patches to ensure bisectability]
Signed-off-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Otavio Salvador <otavio@ossystems.com.br> [dw_mmc portion]
Reviewed-by: Fabio Estevam <festevam@gmail.com> [mxsmmc portion]
Reviewed-by: Simon Glass <sjg@chromium.org> [tegra portion]
diff --git a/configs/zc5601_defconfig b/configs/zc5601_defconfig
index e92c63d..1105b9f 100644
--- a/configs/zc5601_defconfig
+++ b/configs/zc5601_defconfig
@@ -17,6 +17,7 @@
 CONFIG_BOOTDELAY=3
 CONFIG_BOOTCOMMAND="run findfdt; run distro_bootcmd"
 CONFIG_DEFAULT_FDT_FILE="imx6q-zc5601.dtb"
+CONFIG_BOUNCE_BUFFER=y
 CONFIG_BOARD_EARLY_INIT_F=y
 CONFIG_SPL_EXT_SUPPORT=y
 CONFIG_SPL_I2C_SUPPORT=y