qemu: Consolidate EXTRA_OECONF

qemu: Consolidate EXTRA_OECONF

Consolidate the configure options into the EXTRA_OECONF variable,
including merging any native(sdk) specific options.

This consolidation also makes the use of 'system' pixman in the
nativesdk case, this is desirable as the QEMU internal pixman may not be
available (using QEMU git as opposed to tarball) and pixman is already
in DEPENDS. Additionally the QEMU configure recommends to use the system
pixman if available.

Additionally move the options specified in the do_configure into the
EXTRA_OECONF variable. And flesh out all the target directories.

(From OE-Core rev: 9d908f6369e938f1da4456dbc07c64f328656182)

Signed-off-by: Nathan Rossi <nathan@nathanrossi.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>