lib: fdtdec: Update ram_base to store ram start adddress

This patch updates the ram_base to store the start address of
the first bank DRAM and the use this ram_base to calculate ram_top
properly. This patch fixes the erroneous calculation of ram_top
incase of non zero ram start address.

Signed-off-by: Siva Durga Prasad Paladugu <siva.durga.paladugu@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Tom Rini <trini@konsulko.com>

diff --git a/lib/fdtdec.c b/lib/fdtdec.c
index 1b0c430..66dff0f 100644
--- a/lib/fdtdec.c
+++ b/lib/fdtdec.c
@@ -1173,6 +1173,7 @@
 	}
 
 	gd->ram_size = (phys_size_t)(res.end - res.start + 1);
+	gd->ram_base = (unsigned long)res.start;
 	debug("%s: Initial DRAM size %llx\n", __func__,
 	      (unsigned long long)gd->ram_size);