lightnvm: rename nr_pages to nr_ppas on nvm_rq

The number of ppas contained on a request is not necessarily the number
of pages that it maps to neither on the target nor on the device side.
In order to avoid confusion, rename nr_pages to nr_ppas since it is what
the variable actually contains.

Signed-off-by: Javier González <javier@cnexlabs.com>
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 3a810d7..b2991c7 100644
--- a/include/linux/lightnvm.h
+++ b/include/linux/lightnvm.h
@@ -244,7 +244,7 @@
 	nvm_end_io_fn *end_io;
 
 	uint8_t opcode;
-	uint16_t nr_pages;
+	uint16_t nr_ppas;
 	uint16_t flags;
 
 	u64 ppa_status; /* ppa media status */