cmd: mac: Update description of help

Update help message for "mac" command to reflect correct descriptions
and parameters.

Signed-off-by: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>
diff --git a/cmd/mac.c b/cmd/mac.c
index 52d3ba0..4d0dd2b 100644
--- a/cmd/mac.c
+++ b/cmd/mac.c
@@ -13,21 +13,21 @@
 U_BOOT_CMD(
 	mac, 3, 1,  do_mac,
 	"display and program the system ID and MAC addresses in EEPROM",
-	"[read|save|id|num|errata|date|ports|0|1|2|3|4|5|6|7]\n"
+	"[read|save|id|num|errata|date|ports|port_number]\n"
 	"mac read\n"
-	"    - read EEPROM content into memory\n"
+	"    - read EEPROM content into memory data structure\n"
 	"mac save\n"
-	"    - save to the EEPROM\n"
+	"    - save memory data structure to the EEPROM\n"
 	"mac id\n"
-	"    - program system id\n"
-	"mac num\n"
-	"    - program system serial number\n"
-	"mac errata\n"
-	"    - program errata data\n"
-	"mac date\n"
-	"    - program date\n"
-	"mac ports\n"
-	"    - program the number of ports\n"
-	"mac X\n"
-	"    - program the MAC address for port X [X=0...7]"
+	"    - program system id per hard coded value\n"
+	"mac num string\n"
+	"    - program system serial number to value string\n"
+	"mac errata string\n"
+	"    - program errata data to value string\n"
+	"mac date YYMMDDhhmmss\n"
+	"    - program date to string value YYMMDDhhmmss\n"
+	"mac ports N\n"
+	"    - program the number of network ports to integer N\n"
+	"mac X string\n"
+	"    - program MAC addr for port X [X=0,1..] to colon separated string"
 );