lightnvm: reduce number of nvm_id groups to one

The number of configuration groups has been limited to one in current
code, even if there is support for up to four. With the introduction
of the open-channel SSD 1.3 specification, only a single
group is exposed onwards. Reflect this in the nvm_id structure.

Signed-off-by: Matias Bjørling <matias@cnexlabs.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/include/linux/lightnvm.h b/include/linux/lightnvm.h
index faa0fbf..ce0b2da 100644
--- a/include/linux/lightnvm.h
+++ b/include/linux/lightnvm.h
@@ -200,11 +200,10 @@ struct nvm_addr_format {
 struct nvm_id {
 	u8	ver_id;
 	u8	vmnt;
-	u8	cgrps;
 	u32	cap;
 	u32	dom;
 	struct nvm_addr_format ppaf;
-	struct nvm_id_group groups[4];
+	struct nvm_id_group grp;
 } __packed;
 
 struct nvm_target {