Revert "UBUNTU: [Config] Enable CONFIG_NVRAM=m"

Revert "UBUNTU: [Config] Enable CONFIG_NVRAM=m"

BugLink: http://bugs.launchpad.net/bugs/942193

This reverts commit 2fc20ccc8d8b2fc43fda81905eecb0c0c744cd94.

CONFIG_NVRAM was originally built in on powerpc but then changed to be
enabled as a module during the Precise config review as there was no
supporting evidence for it to be built in.  However, there is a bug
report stating that this change prevents 'ybin' (the program which
configures the PowerPC bootloader) from working.  So revert this change
and follow up with another commit to add this to the enforcer.

Signed-off-by: Leann Ogasawara <leann.ogasawara@canonical.com>