macintosh/nvram: Remove as unused

The full history Linux tree says it was moved:

  commit 17c6f4635bea74e110ab3558d408c9cd218c568a
  Author: Benjamin Herrenschmidt <benh@kernel.crashing.org>
  Date:   Fri Feb 6 14:20:56 2004 +1100

      ppc32: Rework nvram management

      move drivers/macintosh/nvram.c to drivers/char/generic_nvram.c,
      update platform hooks,
      fix powermac nvram driver for newer machines

But it's still there, and not buildable, so remove it.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>