sstate: Stop overwriting SSTATE_PKG
Its rather antisocial to overwrite SSTATE_PKG with an expanded form for the variable
and it stops the value of BB_UNIHASH being changed when the package is written out.
Instead of expanding the variable, append to it instead to avoid this rather
hard to figure out behaviour and allow the siggen code to behave as expected.
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit
62eca02024b4c44d618ab9bcf87a3166c886dadb)
Signed-off-by: Armin Kuster <akuster808@gmail.com>
