MIPS: rename rollback_handler with skipover_handler

Recently the rollback region has been changed into an
idle interrupt region [1]. This patch make the appropriate
changes renaming functions and macro, to reflect the change.

[1] https://lore.kernel.org/linux-mips/20250403161143.361461-2-marco.crivellari@suse.com/



Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>