target-xtensa: fix cross-page jumps/calls at the end of TB

Use tb->pc instead of dc->pc to check for cross-page jumps.
When TB translation stops at the page boundary dc->pc points to the next
page allowing chaining to TBs in it, which is wrong.

Cc: qemu-stable@nongnu.org
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
