ARM: dts: AM33XX: Convert all hex numbers to lower-case

To make it consistent, convert all hex number presentation
to lower-case from all am33xx specific nodes.

Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
Cc: Tony Lindgren <tony@atomide.com>
Signed-off-by: Benoit Cousson <b-cousson@ti.com>