staging:ti dspbridge: fix bridge_brd_stop so IVA2 is set OFF

right now, bridge_brd_stop is not changing the IVA2 power state
to OFF since PM_PWSTST_IVA2 is not 0 after calling this function.

Signed-off-by: Ernesto Ramos <ernesto@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>