powerpc/pseries: radix is not subject to RMA limit, remove it

The radix guest is not subject to the paravirtualized HPT VRMA limit,
so remove that from ppc64_rma_size calculation for that platform.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/mm/pgtable-radix.c

@@ -631,15 +631,12 @@ void radix__setup_initial_memory_limit(phys_addr_t first_memblock_base,
 
 	if (!early_cpu_has_feature(CPU_FTR_HVMODE)) {
 		/*
-		 * We limit the allocation that depend on ppc64_rma_size
-		 * to first_memblock_size. We also clamp it to 1GB to
-		 * avoid some funky things such as RTAS bugs.
+		 * Radix mode guests are not limited by RMA / VRMA addressing.
 		 *
-		 * On radix config we really don't have a limitation
-		 * on real mode access. But keeping it as above works
-		 * well enough.
+		 * We do clamp addresses to 1GB to avoid some funky things
+		 * such as RTAS bugs.
 		 */
-		ppc64_rma_size = min_t(u64, first_memblock_size, 0x40000000);
+		ppc64_rma_size = 0x40000000;
 		/*
 		 * Finally limit subsequent allocations. We really don't want
 		 * to limit the memblock allocations to rma_size. FIXME!! should