bus: ti-sysc: Fix build warning for 64-bit build

Fix "warning: cast from pointer to integer of different size" on 64-bit
builds.

Note that this is a cosmetic fix at this point as the driver is not yet
used for 64-bit systems.

Fixes: feaa8bae ("bus: ti-sysc: Implement SoC revision handling")
Reviewed-by: Dhruva Gole <d-gole@ti.com>
Reviewed-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>