doc: nrf: nrf.doxyfile.in: allow doxygen to run in parallel

Parallel threads base on system capabilites.

Signed-off-by: Piotr Kosycarz <[email protected]>

Author: nordic-piks

doc/nrf/nrf.doxyfile.in

@@ -493,7 +493,7 @@ LOOKUP_CACHE_SIZE      = 9
 # DOT_NUM_THREADS setting.
 # Minimum value: 0, maximum value: 32, default value: 1.
 
-NUM_PROC_THREADS       = 1
+NUM_PROC_THREADS       = 0
 
 # If the TIMESTAMP tag is set different from NO then each generated page will
 # contain the date or date and time when the page was generated. Setting this to