soc/ucb/riscv: Place CBMEM at top of autodetected RAM

Change-Id: Ida016aec11ccdb8da8d2ae1d30ddca16b069be11
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Reviewed-on: https://review.coreboot.org/17595
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
1 file changed