livepatch-gcc: Allow toolchain command with versions

livepatch-gcc: Allow toolchain command with versions

Xen build system may enforce particular gcc version (e.g. gcc72).
Make sure the livepatch-gcc script accepts all input toolchain gcc
commands with or without version specified.

Signed-off-by: Pawel Wieczorkiewicz <wipawel@amazon.de>
Reviewed-by: Martin Mazein <amazein@amazon.de>
Reviewed-by: Bjoern Doebel <doebel@amazon.de>
Reviewed-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>