Remove explicit SRCPV
As of oe-core a8e7b0f, PV doesn't need to contain SRCPV explicitly as
base.bbclass will append it to PKGV if there is a + in the version. So,
remove the redundant assignments.
Also change the boot-wrapper-aarch64 PV to 0+git as it's possible that
some point they'll tag a release and we want to be able to upgrade to it.
Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Jon Mason <jon.mason@arm.com>