RK3568 4GB bootsource problem

[Alexander Shiyan]

Hello All.

Another problem with the boot on the RK3568.
In the version with 2Gb DRAM memory everything works fine.
When running the board version with 4Gb DRAM, the bootsource value
is determined incorrectly, although the value in SRAM is correct.

Board: Diasom DS-RK3568-EVB
deep-probe: supported due to diasom,ds-rk3568-evb
bs addr 0xefff8010 value 0xc0400611
...
Boot source: unknown, instance -1
...
Hit any to stop autoboot:    2
barebox at Diasom DS-RK3568-EVB:/ md 0xfdcc0000
fdcc0000: 00000190 deadbeaf 0005e438 00000000                ........8.......
fdcc0010: 0000000a e7fdfadb 7afd3b58 ef57f7bb                ........X;.z..W.
...
barebox at Diasom DS-RK3568-EVB:/ md 0xefff8000
efff8000: c0000611 00000000 c0200611 00000000                .......... .....
efff8010: c0400611 00000000 c0600611 00000000                .. at .......`.....