Fix a buffer overrun error when attempting to parse corrupt DWARF information.

Fix a buffer overrun error when attempting to parse corrupt DWARF information.

	PR 24334
	* dwarf2.c (struct dwarf2_debug): Add sec_vma_count field.
	(save_section_vma): Initialise field to the number of entries in
	the sec_vma table.
	(section_vma_same): Check that the number of entries in the
	sec_vma table matches the number of sections in the bfd.