fix(armbian-firstlogin): use PRESET_USER_KEY instead of PRESET_ROOT_KEY for user SSH key

Author: vascoguita

packages/bsp/common/usr/lib/armbian/armbian-firstlogin

@@ -587,7 +587,7 @@ add_user() {
 			# download and add SSH key if defined
 			if [[ -n "${PRESET_USER_KEY}" ]]; then
 				mkdir -p /home/"$RealUserName"/.ssh/
-				curl --retry 5 --connect-timeout 3 "${PRESET_ROOT_KEY}" > /home/"$RealUserName"/.ssh/authorized_keys 2> /dev/null
+				curl --retry 5 --connect-timeout 3 "${PRESET_USER_KEY}" > /home/"$RealUserName"/.ssh/authorized_keys 2> /dev/null
 				chown -R "$RealUserName":"$RealUserName" /home/"$RealUserName"/.ssh/
 			fi