classes/package_deb: add PackageArch field

If we want to query the PACKAGE_ARCH from the installed package (as we
do in order to be able to do a pkgdata lookup for example) then we need
to have this stored in its own field as this is not always the same as
the Architecture field for deb packages.

(From OE-Core rev: 3f4f6726646e18ae21919e2f361b669332796aef)

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/package_deb.bbclass

@@ -290,6 +290,7 @@ python do_package_deb () {
         fields.append(["Maintainer: %s\n", ['MAINTAINER']])
         fields.append(["Architecture: %s\n", ['DPKG_ARCH']])
         fields.append(["OE: %s\n", ['PN']])
+        fields.append(["PackageArch: %s\n", ['PACKAGE_ARCH']])
         fields.append(["Homepage: %s\n", ['HOMEPAGE']])
 
         # Package, Version, Maintainer, Description - mandatory