ARM: pxa/corgi: Remove hardcoded partitioning, use sharpslpart parser

ARM: pxa/corgi: Remove hardcoded partitioning, use sharpslpart parser

With the introduction of sharpslpart partition parser we can now read the
offsets from NAND: we specify the list of the parsers as platform data, with
cmdlinepart and ofpart parsers first allowing to override the part. table
written in NAND. This is done here in the board file.

Emulators like qemu will need to pass the mtdparts in the cmdline.

Signed-off-by: Andrea Adami <andrea.adami@gmail.com>
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>