ARM: OMAP4430: PMU: prepare to create PMU device via HWMOD

For OMAP4430 PMU events are routed to the CPU via the cross trigger interface
(CTI) because there are no dedicated interrupts. In order to route the PMU
events via the CTI IRQs, the following modules must be enabled:

        l3_instr, l3_main_3, debugss

Therefore, build the arm-pmu device via these three HWMODs.

However, the CTI support for this platform still needs some work.  Until
that's finished, temporarily disable the PMU on OMAP4430.

Cc: Ming Lei <ming.lei@canonical.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Kevin Hilman <khilman@ti.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Jon Hunter <jon-hunter@ti.com>
[paul@pwsan.com: temporarily disabled OMAP4430 PMU support until a
 better CTI interface can be implemented; added patch description note]
Signed-off-by: Paul Walmsley <paul@pwsan.com>