.idata symbols should be reported with i or I flag by nm

	PR 24511
	* syms.c (stt): Trim off all but 'e', 'i' and 'p' entries.
	(coff_section_type): Adjust comment.
	(decode_section_type): Likewise.  Call coff_section_type before
	decode_section_type.
	(bfd_decode_symclass): Use 'c' for common sections other than
	the standard one.