powerpc/kprobes: Remove redundant code

At the time being we have something like

	if (something) {
		p = get();
		if (p) {
			if (something_wrong)
				goto out;
			...
			return;
		} else if (a != b) {
			if (some_error)
				goto out;
			...
		}
		goto out;
	}
	p = get();
	if (!p) {
		if (a != b) {
			if (some_error)
				goto out;
			...
		}
		goto out;
	}

This is similar to

	p = get();
	if (!p) {
		if (a != b) {
			if (some_error)
				goto out;
			...
		}
		goto out;
	}
	if (something) {
		if (something_wrong)
			goto out;
		...
		return;
	}

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[mpe: Reflow the comment that was moved]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/07a17425743600460ce35fa9432d42487a825583.1582099499.git.christophe.leroy@c-s.fr