This patch consists of the following:
1. NAND Flash Controller (NFC) pin configuration.
2. NFC clock configuration (enable the clock, initialize the clock rate.)
3. Changes to the `fsl_nfc` NFC driver:
     * Code cleanup (there were compilation warnings, e.g. unused data
         and functions.)
     * `#include <asm/immap.h>` should not be used on ARM.
     * Disable the GPIO configuration code on ARM.
     * Use `__raw_writel/__raw_readl` instead of `out_be32/in_be32`.
         The registers of the NAND Flash Controller always use the
         same endianness as the MCU core.
     * Make the code in fsl_nfc_get_id() and fsl_nfc_get_status()
         endianness-independent (they were accessing the data from
         32-bit register as an array of u8, this approach is
         endianness-dependent.)
4. NAND support in the U-Boot configuration file.
5. Support for environment in the NAND flash in the U-Boot configuration
     file.
6. Increase the size of the `RAM` memory region to fit the statically
allocated data for the NAND driver and the U-Boot framework for NAND.