docs: remove deprecated doxygen options

Noticed those with most recent doxygen, we do not use those options, so
it is safe to remove now.

[Backport of f2b04d9]

Signed-off-by: Anas Nashif <[email protected]>
Signed-off-by: Kumar Gala <[email protected]>

Author: nashif

doc/zephyr.doxyfile.in

@@ -2066,12 +2066,6 @@ EXTERNAL_GROUPS        = YES
 
 EXTERNAL_PAGES         = YES
 
-# The PERL_PATH should be the absolute path and name of the perl script
-# interpreter (i.e. the result of 'which perl').
-# The default file (with absolute path) is: /usr/bin/perl.
-
-PERL_PATH              = /usr/bin/perl
-
 #---------------------------------------------------------------------------
 # Configuration options related to the dot tool
 #---------------------------------------------------------------------------
@@ -2085,15 +2079,6 @@ PERL_PATH              = /usr/bin/perl
 
 CLASS_DIAGRAMS         = NO
 
-# You can define message sequence charts within doxygen comments using the \msc
-# command. Doxygen will then run the mscgen tool (see:
-# http://www.mcternan.me.uk/mscgen/)) to produce the chart and insert it in the
-# documentation. The MSCGEN_PATH tag allows you to specify the directory where
-# the mscgen tool resides. If left empty the tool is assumed to be found in the
-# default search path.
-
-MSCGEN_PATH            =
-
 # You can include diagrams made with dia in doxygen documentation. Doxygen will
 # then run dia to produce the diagram and insert it in the documentation. The
 # DIA_PATH tag allows you to specify the directory where the dia binary resides.