ARM: dts: imx51-babbage: Fix esdhc setup

Since commit 89d7e5c13122 (mmc: sdhci-esdhc-imx: add runtime pm
support), controller based card detection / write protection is not
supported anymore by esdhc driver.  Let's use GPIO for CD/WP on esdhc1
instead.

While at it, fix cd gpio polarity for esdhc2. This is wrong and
currently only works because the imx esdhc driver ignores the polarity.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Shawn Guo <shawn.guo@freescale.com>