doxygen: include all target headers

Even if they haven't been referenced from a .c file.  Some peripherals
start their life as register definitions only, and they should still
have the documentation generated.

There _will_ be overlap in the generated lists, but doxygen doesn't seem
to mind this.

scripts/gendoxylist

@@ -6,14 +6,17 @@
 DDIR=$1
 ODIR=$2
 ONAME=doxy.sourcelist
+IPATH=$(echo ${DDIR} | sed -e 's#../lib/##')
 
 PATH_DELTA=$(realpath --relative-to=${ODIR} ${DDIR})
 
 printf "# This file is autogenerated by scripts/gendoxylist\n" > ${ODIR}/${ONAME}
-printf "# Documentation only header, not caught by .d file tracking" >> ${ODIR}/${ONAME}
-FN=$(find ../include/libopencm3/ -name doc-$(basename ${ODIR}).h)
-printf "INPUT += ../%s\n" "$FN" > ${ODIR}/${ONAME}
+printf "# All headers for platform, not always caught by .d file tracking" >> ${ODIR}/${ONAME}
+for FN in FN=$(find ../include/libopencm3/${IPATH} -name '*.h'); do
+	printf "INPUT += ../%s\n" "$FN" >> ${ODIR}/${ONAME}
+done
 
+# There will be duplicates here, but doxygen doesn't mind.
 printf "# Headers first\n" >> ${ODIR}/${ONAME}
 grep -o '[^ ]*.h' ${DDIR}/*.d | grep 'include/libopencm3' | cut -d ':' -f2 | sort | uniq | sed "s#^#INPUT += ${PATH_DELTA}/#" >> ${ODIR}/${ONAME}