genext2fs.inc: Add nativesdk build capability

genext2fs.inc: Add nativesdk build capability

In order to generate new disk images for ext(2,3,4) which contain root
file systems we do not want to rely on the host's genext2fs which may
have different arguments and features, so allow the nativesdk
genext2fs binary to be built.

(From OE-Core rev: b9eac9683baaeb458d70a5089cbb5e2b8149eb26)

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>