UBUNTU: [Packaging] Update dependency of pahole / dwarves

UBUNTU: [Packaging] Update dependency of pahole / dwarves

We need pahole >= 1.21 to properly support BTF, pahole used to be
provided by dwarves, but this package is going to be renamed into pahole
starting with jammy.

So to be as generic as possible, and facilitate the porting of this rule
across all kernels, specify a single dependency as following:

 - if we are in jammy => just depend on pahole
 - all the releases < jammy => depend on dwarves >= 1.21

Also add riscv64 to the list of architectures that require pahole.

Signed-off-by: Andrea Righi <andrea.righi@canonical.com>