LDSCRIPT: Name INIT_RAM_FS consistently

In asm-generic/vmlinux.lds.h, name INIT_RAM_FS consistently, no matter the
setting of CONFIG_BLK_DEV_INITRD.  This corrects:

	commit ef53dae8
	Author: Sam Ravnborg <sam@ravnborg.org>
	Date:   Sun Jun 7 20:46:37 2009 +0200
	Subject: Improve vmlinux.lds.h support for arch specific linker scripts
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/asm-generic/vmlinux.lds.h

@@ -625,7 +625,7 @@
 	*(.init.ramfs)							\
 	VMLINUX_SYMBOL(__initramfs_end) = .;
 #else
-#define INITRAMFS
+#define INIT_RAM_FS
 #endif
 
 /**