s390: Improve diagnostic for reloc against misaligned sym

s390: Improve diagnostic for reloc against misaligned sym

Report the BFD in which a misaligned symbol is defined in the error
message.  This complements commit 906f69cf65da ("IBM zSystems: Issue
error for *DBL relocs on misaligned symbols").  While at it reword
the error message.

Old error message text (re-wrapped):
<sec-bfd>(<sec>+<off>): misaligned symbol `<sym>' (<addr>) for
                        relocation <rel>

New error message text (re-wrapped):
<sec-bfd>(<sec>+<off>): relocation <rel> against misaligned symbol
                        `<sym>' (<addr>) in <sym-bfd>

Note that the linker tests do not require to be updated, as they match
against the pattern ".*misaligned symbol.*", which has not changed in
the error message.

bfd/
	PR ld/32969
	* elf64-s390.c (elf_s390_relocate_section): Report BFD
	in which a misaligned symbol is defined in error message.

Bug: https://sourceware.org/PR32969
Suggested-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Jens Remus <jremus@linux.ibm.com>