ARM: dts: omap3-pandora: miscellaneous corrections

- add pandora specific compatible name
- fix mmc2 card detect polarity
- fix mmc1 and mmc2 write protect polarity
- disable write protect pins because of production issue and add an
  explanation why they are disabled
- fix NAND partition name to reflect the correct address

Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>