[ARC] Fixed condition to generate TEXTREL.

TEXTREL was being generated even when relocatable .o files had the .rela.text
section. Now it is limitted only to dynamic object files that still have them.
Nevertheless, our target aborts in those cases due to architecture limitations
where icache is not coherent with dcache, and to force this coherence expensive
kernel level support would be needed.

bfd/ChangeLog:

    Cupertino Miranda  <cmiranda@synopsys.com>

	* elf32-arc.c (elf_arc_size_dynamic_sections): Changed condition to
	require TEXTREL.