keystone2: add possibility to turn off all dsps

By default all DSPs are turned off, for another case option
to turn off them is added in this commit.
Also add command to turn off itself.

Acked-by: Murali Karicheri <m-maricheri2@ti.com>
Signed-off-by: Hao Zhang <hzhang@ti.com>
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>
4 files changed