bus: omap_l3_noc: convert flagmux information into a structure

This allows us to encompass target information and flag mux offset that
points to the target information into a singular structure. This saves
us the need to look up two different arrays indexed by module ID for
information.

This allows us to reduce the static target information allocation to
just the ones that are documented.

Signed-off-by: Nishanth Menon <nm@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Tested-by: Darren Etheridge <detheridge@ti.com>
Tested-by: Sekhar Nori <nsekhar@ti.com>