[reboot] No need enable the Linux magic system request key (sonic-net#1538)

As introduced by the kernel doc, we do not need the line 20 in reboot script since it only influenced the capability to reboot the Linux kernel by hitting the combo magic key of keyboard.

Signed-off-by: Yong Zhao <[email protected]>

Author: yozhao101

scripts/reboot

@@ -17,7 +17,6 @@ if [ -e $VMCORE_FILE -a -s $VMCORE_FILE ]; then
         fi
         # If no platform-specific reboot tool, just run /sbin/reboot
         /sbin/reboot
-        echo 1 > /proc/sys/kernel/sysrq
         echo b > /proc/sysrq-trigger
 fi