更新 boot.sh 和 grub.cfg，优化 MEV 变量获取逻辑，并在 grub.cfg 中添加 MEV 输出

files/initrd/opt/rr/boot.sh

@@ -68,7 +68,7 @@ DT="$(readConfigKey "platforms.${PLATFORM}.dt" "${WORK_PATH}/platforms.yml")"
 KVER="$(readConfigKey "platforms.${PLATFORM}.productvers.\"${PRODUCTVER}\".kver" "${WORK_PATH}/platforms.yml")"
 KPRE="$(readConfigKey "platforms.${PLATFORM}.productvers.\"${PRODUCTVER}\".kpre" "${WORK_PATH}/platforms.yml")"
 
-MEV="$(virt-what 2>/dev/null)"
+MEV="$(virt-what 2>/dev/null | head -1)"
 DMI="$(dmesg 2>/dev/null | grep -i "DMI:" | head -1 | sed 's/\[.*\] DMI: //i')"
 CPU="$(awk -F': ' '/model name/ {print $2}' /proc/cpuinfo | uniq)"
 MEM="$(awk '/MemTotal:/ {printf "%.0f", $2 / 1024}' /proc/meminfo) MB"