To remove suspend from quit dialog in Mate execute the following commands:

sudo touch /etc/polkit-1/localauthority/90-mandatory.d/disable-suspend.pkla
gksudo pluma /etc/polkit-1/localauthority/90-mandatory.d/disable-suspend.pkla

when text editor opens copy the text below and paste it in text editor and save it.

[Disable suspend (upower)]
Identity=unix-user:*
Action=org.freedesktop.upower.suspend
ResultActive=no
ResultInactive=no
ResultAny=no

[Disable suspend (logind)]
Identity=unix-user:*
Action=org.freedesktop.login1.suspend
ResultActive=no

[Disable suspend for all sessions (logind)]
Identity=unix-user:*
Action=org.freedesktop.login1.suspend-multiple-sessions
ResultActive=no

To remove suspend from quit dialog in Cinnamon execute the following commands:

sudo touch /etc/polkit-1/localauthority/90-mandatory.d/disable-suspend.pkla
gksudo gedit /etc/polkit-1/localauthority/90-mandatory.d/disable-suspend.pkla

when text editor opens copy the text below and paste it in text editor and save it.

[Disable suspend (upower)]
Identity=unix-user:*
Action=org.freedesktop.upower.suspend
ResultActive=no
ResultInactive=no
ResultAny=no

[Disable suspend (logind)]
Identity=unix-user:*
Action=org.freedesktop.login1.suspend
ResultActive=no

[Disable suspend for all sessions (logind)]
Identity=unix-user:*
Action=org.freedesktop.login1.suspend-multiple-sessions
ResultActive=no 

Note: You may have to reboot.