The use of SBMAXEXTENSIONLENGTH appears to be an insane way
to detect full filter names and map them back to short suffixes
but we are passing suffixes separated by | and if that string
hits the SBMAXEXTENSIONLENGTH it gets blanked.

So, lets try only doing the conversion to suffix if the filter
name starts with a common substr handled by SetExtension

Change-Id: I42914d3e042133a2c5e28c9704b5fded7ca938dc