dt-bindings: change the macro name of prci in header files and example

We currently change the macro name for fu540 and fu740 by adding the
prefix respectively, the dt-bindings should be modified as well.

Signed-off-by: Zong Li <zong.li@sifive.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Link: https://lore.kernel.org/r/f9284873c2993a9952d9fe4f8dd5e89f20daab75.1646388139.git.zong.li@sifive.com


Signed-off-by: Stephen Boyd <sboyd@kernel.org>