mtd: cmdlinepart: minor cleanups

Clean-up the driver a bit to make it easier to read and amend the coding style.
Mostly these are changes like:

if (a)
{
}

=>

if (a) {
}

Some extra blank lines were added.
Indentation was changed to use tabs instead of spaces.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>