[PATCH] ppc64: NVRAM fixes

From: Anton Blanchard <anton@samba.org>

We check nvram_fetch/nvram_store against -1, so better not make these
unsigned.

arch/ppc64/kernel/pSeries_nvram.c

@@ -29,7 +29,7 @@
 #include <asm/machdep.h>
 
 static unsigned int nvram_size;
-static unsigned int nvram_fetch, nvram_store;
+static int nvram_fetch, nvram_store;
 static char nvram_buf[NVRW_CNT];	/* assume this is in the first 4GB */
 static spinlock_t nvram_lock = SPIN_LOCK_UNLOCKED;