lightnvm: add fpg_size and pfpg_size to struct nvm_dev

The flash page size (fpg) and size across planes (pfpg) are convenient
to know when allocating buffer sizes. This has previously been a
calculated in various places. Replace with the pre-calculated values.

Reviewed by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/include/linux/lightnvm.h b/include/linux/lightnvm.h
index 38814e2..f7c607f 100644
--- a/include/linux/lightnvm.h
+++ b/include/linux/lightnvm.h
@@ -323,6 +323,8 @@
 	int sec_per_pg; /* only sectors for a single page */
 	int pgs_per_blk;
 	int blks_per_lun;
+	int fpg_size;
+	int pfpg_size; /* size of buffer if all pages are to be read */
 	int sec_size;
 	int oob_size;
 	int mccap;