docs/help: rename defconfig/olddefconfig into

After commit 15f57d843296e244487ac0845a73247f9d6749b8, the defconfig target
has been renamed into savedefconfig, and olddefconfig into defconfig. However,
the help text and man page was not updated.

Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
[yann.morin.1998@free.fr: rename CONFIG -> DEFCONFIG]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Message-Id: <0c1dff89c9ee1672693f.1374042343@BEANTN0L019720>
Patchwork-Id: 259601

# Super-H specific configuration file

## select ARCH_SUPPORTS_32

## select ARCH_DEFAULT_32

## select ARCH_USE_MMU

## select ARCH_SUPPORTS_BOTH_ENDIAN

## select ARCH_DEFAULT_LE

##

## help The Super-H architecture, as defined by:

## help     http://www.renesas.com/fmwk.jsp?cnt=superh_family_landing.jsp&fp=/products/mpumcu/superh_family/