OMAP3 clock: OMAP3430ES2+ has SSI target idlest bit

On OMAP3430ES2+, SSI has both an initiator standby CM_IDLEST bit, and a
target idle CM_IDLEST bit.  This is a departure from previous silicon,
which only had an initiator standby bit.

This means that omap2_clk_wait_ready() needs to wait for the SSI
module to indicate readiness after both SSI interface and functional
clocks are enabled.

Thanks to Igor Stoppa <igor.stoppa@nokia.com>, Richard Woodruff
<r-woodruff2@ti.com>, and Jouni Högander <jouni.hogander@nokia.com> for
help with this portion of the patch.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>