xtensa: don't touch EXC_TABLE_FIXUP in _switch_to
xtensa: don't touch EXC_TABLE_FIXUP in _switch_to

There's no way _switch_to can produce double exceptions now, don't
enter/leave EXC_TABLE_FIXUP critical section.

Signed-off-by: Max Filippov <8c5ea195856807f4f02a6e0749c87ea6b7375f38@gmail.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs