fs/proc/vmcore.c: Convert to use vmf_error()

This code can be replaced with vmf_error() inline function.

Link: http://lkml.kernel.org/r/20180918145945.GA11392@jordon-HP-15-Notebook-PC
Signed-off-by: Souptick Joarder <[e-mail]>
Reviewed-by: Matthew Wilcox <[e-mail]>
Cc: Alexey Dobriyan <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

fs/proc/vmcore.c

···
 		if (rc < 0) {
 			unlock_page(page);
 			put_page(page);
-			return (rc == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS;
+			return vmf_error(rc);
 		}
 		SetPageUptodate(page);
 	}