aes: Add 'aes' command to access AES-128-CBC

Add simple 'aes' command, which allows using the AES-128-CBC encryption
and decryption functions from U-Boot command line.

Signed-off-by: Marek Vasut <marex@denx.de>
diff --git a/README b/README
index 216f0c7..fd717bf 100644
--- a/README
+++ b/README
@@ -910,6 +910,7 @@
 		The default command configuration includes all commands
 		except those marked below with a "*".
 
+		CONFIG_CMD_AES		  AES 128 CBC encrypt/decrypt
 		CONFIG_CMD_ASKENV	* ask for env variable
 		CONFIG_CMD_BDI		  bdinfo
 		CONFIG_CMD_BEDBUG	* Include BedBug Debugger