filetop: Add missing entry of -a in the SYNOPSIS section
filetop: Add missing entry of -a in the SYNOPSIS section

Signed-off-by: Vaibhav Nagare <466b64402772fe358355960f6ab5e91adf9324eb@redhat.com>

iovisor/bcc,iovisor/bcc,iovisor/bcc,iovisor/bcc,iovisor/bcc