staging: Separate out different multiconfig manifests

staging: Separate out different multiconfig manifests

"""
require conf/multilib.conf
MACHINE = "qemuarm64"
MULTILIBS = "multilib:lib32"
DEFAULTTUNE:virtclass-multilib-lib32 = "armv7athf-neon"

bitbake gcc-cross-canadian-arm
"""

and then inspecting the lib32* manifest files under recipe-sysroot-native shows
them referencing lib32-recipe-sysroot instead of recipe-sysroot as used by
gcc-cross-canadian recipes.

To fix this separate out the manifest by multilib. It is caching mechanism to
optimise disk usage so this doesn't break anything, just separated out some files.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
(cherry picked from commit 891d3faa3ed3d1cc231da58e5fa1325f05d5ade5)
Signed-off-by: Steve Sakoman <steve@sakoman.com>