pdbg: Bump version to v2.2
Upstream changes:
- libpdbg API clean-up
- Path based targetting
- POWER8 sreset fixes
- gdbserver
This also adds the v back to the version string that pdbg's build system
uses, following the recent buildroot changes to remove "v" from package
versions.
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>