package.bbclass: explode the RPROVIDES so we don't think the versions are provides

emit_pkgdata() creates symlinks for each of the RPROVIDES in
pkgdata/MACHINE/runtime-rprovides.  However this string can contain
versions which results in directories called (=2.32), so pass the
RPROVIDES string through bb.utils.explode_deps() to strip the versions
out.

Helps mitigate - but not solve - #13999.

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>