nvme: Adjust the 'nvme' command to use blk_common_cmd()

Instead of having separate code in the 'nvme' command, adjust it to use
the common function.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/doc/README.nvme b/doc/README.nvme
index 3afa912..d9bda23 100644
--- a/doc/README.nvme
+++ b/doc/README.nvme
@@ -50,14 +50,14 @@
 
 To list all of the NVMe hard disks, try:
 
-  => nvme list
+  => nvme info
   Device 0: Vendor: 0x8086 Rev: 8DV10131 Prod: CVFT535600LS400BGN
 	    Type: Hard Disk
 	    Capacity: 381554.0 MB = 372.6 GB (781422768 x 512)
 
 and print out detailed information for controller and namespaces via:
 
-  => nvme info
+  => nvme detail
 
 Raw block read/write to can be done via the 'nvme read/write' commands: