doc: fix reference to nios2-configure-sof tool

Board documentaion for altera_max10 referenced the nios2-configure-sof
tool in arch/nios2/soc/nios2f-zephyr/cpu/ when this tool is actually
part of the Altera Quartus SDK (the .sof FPGA configuration files are
in this folder)

jira: ZEP-2006

Signed-off-by: David B. Kinder <david.b.kinder@intel.com>