cmd_mac: fix help for 'mac read'

In the only implementation of 'mac read', it doesn't display the
contents of the eeprom as the help indicated unless compiled with
DEBUG. It only re-reads the contents of the EEPROM into memory.
Displaying the contents of the EEPROM is done by passing no
arguments to 'mac'.

Signed-off-by: Michael Jones <michael.jones@matrix-vision.de>
Acked-by: Detlev Zundel <dzu@denx.de>

common/cmd_mac.c

@@ -31,7 +31,7 @@ U_BOOT_CMD(
 	"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"
 	"mac read\n"
-	"    - show content of EEPROM\n"
+	"    - read EEPROM content into memory\n"
 	"mac save\n"
 	"    - save to the EEPROM\n"
 	"mac id\n"