[syslinux-iso] Remove devpts and shm entries from fstab

This work is already done by newer initscripts

Signed-off-by: Gerardo Exequiel Pozzi <vmlinuz386@yahoo.com.ar>

configs/syslinux-iso/overlay/etc/fstab

@@ -3,5 +3,3 @@
 #
 # <file system>        <dir>         <type>    <options>          <dump> <pass>
 union                  /             auto      noauto              0      0
-devpts                 /dev/pts      devpts    defaults            0      0
-shm                    /dev/shm      tmpfs     nodev,nosuid        0      0