board: dragonboard410c: fix chainloaded.config

Since c8a74db0c, SYS_INIT_SP_BSS_OFFSET only supports hex encoding.

Signed-off-by: Sam Day <me@samcday.com>
Link: https://patch.msgid.link/20260531-db410c-chainloaded-fix-v1-1-94176aa147d1@samcday.com
Signed-off-by: Casey Connolly <casey.connolly@linaro.org>