oe.sstatesig: align swspec handling with sstate.bbclass
The logic tries to remove the -native suffix from pn to handle this (though it
doesn't succeed, as it doesn't assign the new pn to the variable), but we need
to do more for the swspec tasks than just not set the extrapath, we also need
to change from SSTATE_PKGSPEC to SSTATE_SWSPEC. Alter to correct the spec for
these cases, and also add preconfigure to align with the current logic in
sstate.bbclass, which includes that task as well in the list of tasks to
adjust to use swspec.
[YOCTO #7563]
(From OE-Core master rev:
c9105597763be4bf5bc0ec97cc999566d0f10678)
Signed-off-by: Christopher Larson <kergoth@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
