x86/crash: Remove unnecessary comparison

The ret comparison and return are unnecessary as of commit f296f263
("x86/kexec: Remove walk_iomem_res() call with GART type")

elf_header_exclude_ranges() returns ret in any case, with or without this
comparison.

[ tglx: Use a proper commit reference instead of full SHA ]

Signed-off-by: Nikolas Nyby <nikolas@gnu.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190724041337.8346-1-nikolas@gnu.org