[llvm] [AVR] Fix a crash in AVRInstrInfo::insertIndirectBranch (PR #67324)

[via llvm-commits]

aykevl wrote:

Checked avr-gcc, and it behaves the same as this patch: it emits an `rjmp` if `jmp` isn't available.
Source: https://godbolt.org/z/dao8sq9hd

https://github.com/llvm/llvm-project/pull/67324