platform: msm_shared: add function for number of pages per block

Add function for returning number of pages per block
of NAND memory.

Change-Id: I1009f43ae528d7753a65888a2563be7f98532c3f
diff --git a/platform/msm_shared/qpic_nand.c b/platform/msm_shared/qpic_nand.c
index baba30d..3fec647 100644
--- a/platform/msm_shared/qpic_nand.c
+++ b/platform/msm_shared/qpic_nand.c
@@ -1378,6 +1378,12 @@
 }
 
 unsigned
+flash_num_pages_per_blk(void)
+{
+	return flash.num_pages_per_blk;
+}
+
+unsigned
 flash_spare_size(void)
 {
     return flash.spare_size;