Since there is no need to place output sections in specific order for
relocatable link, we can skip merging flags of other input sections.

	PR ld/19739
	* emultempl/mmo.em (mmo_place_orphan): Don't merge flags of other
	input sections for relocatable link.
	* emultempl/pe.em (gld_${EMULATION_NAME}_place_orphan): Likewise.
	* emultempl/pep.em (gld_${EMULATION_NAME}_place_orphan): Likewise.