ide: add CONFIG_IDE_ARCH_OBSOLETE_DEFAULTS (take 2)

* Add CONFIG_IDE_ARCH_OBSOLETE_DEFAULTS to drivers/ide/Kconfig and use
  it instead of defining IDE_ARCH_OBSOLETE_DEFAULTS in <arch/ide.h>.

v2:
* Define ide_default_irq() in ide-probe.c/ns87415.c if not already defined
  and drop defining ide_default_irq() for CONFIG_IDE_ARCH_OBSOLETE_DEFAULTS=n.

  [ Thanks to Stephen Rothwell and David Miller for noticing the problem. ]

Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/ide.c b/drivers/ide/ide.c
index c2fb5c9..a1a02c7 100644
--- a/drivers/ide/ide.c
+++ b/drivers/ide/ide.c
@@ -165,6 +165,10 @@
 	}
 }
 
+#ifndef CONFIG_IDE_ARCH_OBSOLETE_DEFAULTS
+# define ide_default_io_base(index)	(0)
+# define ide_init_default_irq(base)	(0)
+#endif
 
 /*
  * init_ide_data() sets reasonable default values into all fields