s390: Add .noinstr.text to boot and purgatory linker scripts

Upcoming changes will result in a .noinstr.text section within the
boot and purgatory string.o binary. Explicitly add the new section to
avoid orphaned warnings from the linker.

Reviewed-by: Juergen Christ <jchrist@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

arch/s390/boot/vmlinux.lds.S

@@ -31,6 +31,7 @@ SECTIONS
 		_text = .;	/* Text */
 		*(.text)
 		*(.text.*)
+		*(.noinstr.text)
 		INIT_TEXT
 		_etext = . ;
 	}

arch/s390/purgatory/purgatory.lds.S

@@ -19,6 +19,7 @@ SECTIONS
 		_text = .;	/* Text */
 		*(.text)
 		*(.text.*)
+		*(.noinstr.text)
 		_etext = . ;
 	}
 	.rodata : {