s390: vmlinux.lds.S: handle '.data.rel' sections explicitly

When building with CONFIG_LD_ORPHAN_WARN after selecting
CONFIG_ARCH_HAS_LD_ORPHAN_WARN, there are a lot of warnings around
'.data.rel' sections:

  s390-linux-ld: warning: orphan section `.data.rel' from `kernel/sched/build_utility.o' being placed in section `.data.rel'
  s390-linux-ld: warning: orphan section `.data.rel.local' from `kernel/sched/build_utility.o' being placed in section `.data.rel.local'
  s390-linux-ld: warning: orphan section `.data.rel.ro' from `kernel/sched/build_utility.o' being placed in section `.data.rel.ro'
  s390-linux-ld: warning: orphan section `.data.rel.ro.local' from `kernel/sched/build_utility.o' being placed in section `.data.rel.ro.local'

Describe these in vmlinux.lds.S so there is no more warning and the
sections are placed consistently between linkers.
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Justin Stitt <justinstitt@google.com>
Link: https://lore.kernel.org/r/20240207-s390-lld-and-orphan-warn-v1-2-8a665b3346ab@kernel.orgSigned-off-by: Heiko Carstens <hca@linux.ibm.com>

arch/s390/kernel/vmlinux.lds.S

@@ -59,6 +59,9 @@ SECTIONS
 	} :text = 0x0700
 
 	RO_DATA(PAGE_SIZE)
+	.data.rel.ro : {
+		*(.data.rel.ro .data.rel.ro.*)
+	}
 
 	. = ALIGN(PAGE_SIZE);
 	_sdata = .;		/* Start of data section */
@@ -73,6 +76,9 @@ SECTIONS
 	__end_ro_after_init = .;
 
 	RW_DATA(0x100, PAGE_SIZE, THREAD_SIZE)
+	.data.rel : {
+		*(.data.rel*)
+	}
 	BOOT_DATA_PRESERVED
 
 	. = ALIGN(8);