[POWERPC] Fix building of pmac32 when CONFIG_NVRAM=m

Kamalesh Babulal (kamalesh@linux.vnet.ibm.com) reports that CONFIG_NVRAM=m
is valid in terms of Kconfig but fails to build with:
  Building modules, stage 2.
  MODPOST 1401 modules
ERROR: "pmac_newworld" [arch/powerpc/platforms/powermac/nvram.ko] undefined!
ERROR: "__alloc_bootmem" [arch/powerpc/platforms/powermac/nvram.ko] undefined!
make[1]: *** [__modpost] Error

The arch/powerpc/platforms/powermac/nvram.c code really needs to be
builtin, but as its compilation is dependent on a generic Kconfig
symbol we force nvram.c to be builtin if CONFIG_NVRAM is 'y' or 'm'.

Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/platforms/powermac/setup.c b/arch/powerpc/platforms/powermac/setup.c
index bf44c54..00bd016 100644
--- a/arch/powerpc/platforms/powermac/setup.c
+++ b/arch/powerpc/platforms/powermac/setup.c
@@ -337,7 +337,8 @@
 	find_via_pmu();
 	smu_init();
 
-#if defined(CONFIG_NVRAM) || defined(CONFIG_PPC64)
+#if defined(CONFIG_NVRAM) || defined(CONFIG_NVRAM_MODULE) || \
+    defined(CONFIG_PPC64)
 	pmac_nvram_init();
 #endif