am3/am5: add chosen: base_dtb/base_dtb_timestamp

src/arm/am335x-abbbi.dts

src/arm/am335x-bone-common-no-capemgr.dtsi

src/arm/am335x-bone-common-univ.dtsi

src/arm/am335x-bone-common.dtsi

src/arm/am335x-bone-jtag.dtsi

src/arm/am335x-bone-uboot-univ.dts

src/arm/am335x-bone.dts

src/arm/am335x-boneblack-common.dtsi

src/arm/am335x-boneblack-uboot-univ.dts

src/arm/am335x-boneblack-uboot.dts

src/arm/am335x-boneblack-wireless.dts

src/arm/am335x-boneblack.dts

src/arm/am335x-boneblue.dts

src/arm/am335x-bonegreen-common.dtsi

src/arm/am335x-bonegreen-wireless-common-univ.dtsi

src/arm/am335x-bonegreen-wireless-uboot-univ.dts

src/arm/am335x-bonegreen-wireless.dts

src/arm/am335x-bonegreen.dts

src/arm/am335x-pocketbeagle-common.dtsi

src/arm/am335x-pocketbeagle.dts