Revert back to e26a7e7
Revert "Merge branch 'dev_pic32mz_B'"

This reverts commit e26a7e713953563c02b94d15304b080b41e0c3c3, reversing
changes made to 0710225fe46c5dce3c903c32f909245695e137d8.
Restore common linker script and startup code to 547889f