MIPS/BFD: Don't stop processing on a cross-mode jump conversion error

MIPS/BFD: Don't stop processing on a cross-mode jump conversion error

As with commit ed53407eec9e ("MIPS/BFD: Don't stop processing on
`bfd_reloc_outofrange'") don't bail out right away and instead continue
processing on a cross-mode jump conversion error, so that any further
issues are also reported.  Adjust message formatting accordingly, using
`%X' to abort processing at conclusion.  Remove the full stop from the
end of the message, for consistency across error reporting.

Adjust the corresponding test case accordingly and make it trigger the
error twice.

	bfd/
	* elfxx-mips.c (mips_elf_perform_relocation): Call
	`info->callbacks->einfo' rather than `*_bfd_error_handler' and
	use the `%X%H' format for the cross-mode jump conversion error
	message.  Remove the full stop from the end of the message.
	Continue processing rather than returning failure.

	ld/
	* testsuite/ld-mips-elf/mode-change-error-1a.s: Trigger an error
	twice rather than once.
	* testsuite/ld-mips-elf/mode-change-error-1.d: Adjust
	accordingly.  Remove the full stop from the end of the message.