[SPARC] Fix PR ld/22972

[Jose E. Marchesi]

Hi Eric.
    
    this is a regression present on mainline and 2.30 branch for the corner case 
    of a hidden symbol in a PIC/PIE binary which is subject to both a new-style 
    GOTDATA relocation and an old-style GOT relocation.  In this case, depending 
    on the link order, the R_SPARC_RELATIVE dynamic relocation for the GOT slot 
    needed because of the old-style relocation can be replaced with R_SPARC_NONE 
    coming from the GOTDATA relocation.
    
    The attached patch simply records whether an old-style GOT relocation is seen 
    for a symbol and prevents the R_SPARC_NONE from being generated in this case.
    
    Tested on SPARC64/Linux with a GCC bootstrap, OK for mainline and 2.30 branch?

LGTM
    
    2018-03-22  Eric Botcazou  <ebotcazou@adacore.com>
    
    	PR ld/22972
    bfd/
    	* elfxx-sparc.c (struct _bfd_sparc_elf_link_hash_entry): Add new flag
    	has_old_style_got_reloc.
    	(_bfd_sparc_elf_check_relocs) <GOT relocations>: Set it for old-style
    	relocations.  Fix a couple of long lines.
    	(_bfd_sparc_elf_relocate_section) <R_SPARC_GOTDATA_OP>: Do not generate
    	a R_SPARC_NONE for the GOT slot if the symbol is also subject to old-style
     	GOT relocations.
    
    ld/
    	* testsuite/ld-sparc/sparc.exp: Add test for mixed GOTDATA/GOT relocations.
    	* testsuite/ld-sparc/gotop-hidden.c: New file.
    	* testsuite/ld-sparc/got-hidden32.s: Likewise.
    	* testsuite/ld-sparc/got-hidden64.s: Likewise.
    	* testsuite/ld-sparc/pass.out: Likewise.