Revert "usb: typec: bus: verify partner exists in typec_altmode_attention"

This reverts commit 0ad6bad3 which is
commit f2364330 upstream.

It breaks the Android abi.  It will be brought back later, in an
ABI-safe way, but for now drop it.

Bug: 161946584
Change-Id: I5cc20208598b89d9a80d2b0cbaaa6492e35392bf
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>