newlib: fix extract process for custom version

newlib: fix extract process for custom version

If the user specifies the use of a custom newlib version, the logic in the
extract function was reversed, so this step would fail.

Signed-off-by: Trevor Woerner <trevor.woerner@linaro.org>
[yann.morin.1998@free.fr: keep leading indentation]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Message-Id: <c727adf1b7bd2c1e891d.1393353347@openSUSE-i7>
Patchwork-Id: 324060

# MIPS specific config options

## select ARCH_SUPPORTS_32

## select ARCH_SUPPORTS_64 if EXPERIMENTAL

## select ARCH_DEFAULT_32

## select ARCH_USE_MMU

## select ARCH_SUPPORTS_BOTH_ENDIAN

## select ARCH_DEFAULT_BE

## select ARCH_SUPPORTS_WITH_ARCH

## select ARCH_SUPPORTS_WITH_TUNE

## select ARCH_SUPPORTS_WITH_FLOAT

##

## help The MIPS architecture, as defined by:

## help     http://www.mips.com/