ASI1230: Call gpmc_init() unconditionally. Configure GPMC depending on HWID

Kernel hangs at startup if GPMC has not been initialized.
ASI1230: Nvmem improvements. Improved info displayed on console

Improve nvmem verification. Move nvmem related code to its own file.
Explicitly inform the user about invalid nvmem data.
Display name and number of the partition selected for boot.
ASI1230: Remove available_mem_mb() and user gd->bd->bi_dram[0].size directly