Revert "nvram: increase NVRAM size to 64 KiB"

This reverts commit ff84c27a281bc19df19bc62ee8688cca5586f6e3.
This tool has really broken size handling (many values hardcoded), it
crashes right now in case of NVRAM not filling whole MTD partition.

Conflicts:
	package/utils/nvram/src/nvram.h

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>

SVN-Revision: 45579