We can now just use PM runtime autoidle support as musb core
keeps things enabled when the devctl session bit is set. And
there's no need for dsps_musb_try_idle() so let's just remove
it.

Note that as cppi41 dma is clocked by musb, this only makes
PM work for dsps glue layer if CONFIG_MUSB_PIO_ONLY=y and
cppi41.ko is unloaded. This will get fixed when cppi41.c has
PM runtime implemented.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>