[POWERPC] Fix building of pmac32 when CONFIG_NVRAM=m

Kamalesh Babulal ([e-mail]) 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 <[e-mail]>
Signed-off-by: Paul Mackerras <[e-mail]>

arch/powerpc/platforms/powermac/Makefile

···
 obj-$(CONFIG_PMAC_BACKLIGHT)	+= backlight.o
 obj-$(CONFIG_CPU_FREQ_PMAC)	+= cpufreq_32.o
 obj-$(CONFIG_CPU_FREQ_PMAC64)	+= cpufreq_64.o
-obj-$(CONFIG_NVRAM)		+= nvram.o
+# CONFIG_NVRAM is an arch. independant tristate symbol, for pmac32 we really
+# need this to be a bool.  Cheat here and pretend CONFIG_NVRAM=m is really
+# CONFIG_NVRAM=y
+obj-$(CONFIG_NVRAM:m=y)		+= nvram.o
 # ppc64 pmac doesn't define CONFIG_NVRAM but needs nvram stuff
 obj-$(CONFIG_PPC64)		+= nvram.o
 obj-$(CONFIG_PPC32)		+= bootx_init.o

arch/powerpc/platforms/powermac/setup.c

···
 	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