readelf: Don't error on .debug files with NOBITS .dynamic section.

readelf: Don't error on .debug files with NOBITS .dynamic section.

The fix for PR binutils/17512 added a check for the dynamic segment being
inside the actual ELF file. If not an error message would be produced:

readelf: Error: the dynamic segment offset + size exceeds the size of the file

Unfortunately for separate debuginfo files it is common for the dynamic
segment not being inside the file because the .dynamic section is NOBITS.

Since the check is done unconditionally in process_program_headers and
process_program_headers is always called (to setup dynamic_addr in case
it is needed). The error is produced on any operations done on any .debug
file (even if no program headers or the dynamic segment is used).

If there are section headers then a cross check is done to see if the
.dynamic section is NOBITS in which case dynamic_addr is set to zero
without a warning or error (which is then checked first before any
operation on the dynamic segement is done).

Move the check for the dynamic segment being inside the actual ELF file
after the cross check with the section headers to suppress the error for
.debug files.

binutils/ChangeLog:

	* readelf.c (process_program_headers): Move dynamic_addr check
	after .dynamic section cross check.