powerpc/nvram: Move things out of asm/nvram.h

This moves a bunch of definitions out of asm/nvram.h to the files
that use them or just outright remove completely unused stuff.

We leave the partition signatures definitions, they will be useful

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/chrp/time.c

@@ -29,6 +29,10 @@
 
 extern spinlock_t rtc_lock;
 
+#define NVRAM_AS0  0x74
+#define NVRAM_AS1  0x75
+#define NVRAM_DATA 0x77
+
 static int nvram_as1 = NVRAM_AS1;
 static int nvram_as0 = NVRAM_AS0;
 static int nvram_data = NVRAM_DATA;