objtool: Return canonical symbol when aliases exist in symbol finding helpers

objtool: Return canonical symbol when aliases exist in symbol finding helpers

When symbol alias ambiguity exists in the symbol finding helper
functions, return the canonical sym->alias, as that's the one which gets
used by validate_branch() and elsewhere.

This doesn't fix any known issues, just makes the symbol alias behavior
more robust.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/450470a4897706af77453ad333e18af5ebab653c.1763671318.git.jpoimboe@kernel.org