ARM: OMAP2+: Use of_address_to_resource()

Replace open coded parsing of "reg" with of_address_to_resource().

Signed-off-by: Rob Herring <robh@kernel.org>
Message-Id: <20230319163135.225076-1-robh@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>