powerpc: Add gpages reservation code for 64-bit FSL BOOKE

For 64-bit FSL_BOOKE implementations, gigantic pages need to be
reserved at boot time by the memblock code based on the command line.
This adds the call that handles the reservation, and fixes some code
comments.

It also removes the previous pr_err when reserve_hugetlb_gpages
is called on a system without hugetlb enabled - the way the code is
structured, the call is unconditional and the resulting error message
spurious and confusing.

Signed-off-by: Becky Bruce <beckyb@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 7c7cb97..79c575d 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -28,10 +28,10 @@
 
 /*
  * Tracks gpages after the device tree is scanned and before the
- * huge_boot_pages list is ready.  On 64-bit implementations, this is
- * just used to track 16G pages and so is a single array.  32-bit
- * implementations may have more than one gpage size due to limitations
- * of the memory allocators, so we need multiple arrays
+ * huge_boot_pages list is ready.  On non-Freescale implementations, this is
+ * just used to track 16G pages and so is a single array.  FSL-based
+ * implementations may have more than one gpage size, so we need multiple
+ * arrays
  */
 #ifdef CONFIG_PPC_FSL_BOOK3E
 #define MAX_NUMBER_GPAGES	128