arm: dts: k3-am625: Drop SoC provided bootph params from board u-boot/r5 dtsi

k3-am62* SoC dtsi files now provide the following:

bootph-all: dmss secure_proxy_main dmsc k3_pds k3_clks k3_reset
   main_pmx0 main_timer0 mcu_pmx0 wkup_conf chipid

bootph-pre-ram: secure_proxy_sa3 main_esm mcu_esm

Drop these from board r5 and u-boot.dtsi files as these are duplicate in
them now.

Acked-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Tested-by: Dhruva Gole <d-gole@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>