make MODEM SUPPORT generic instead of duplicate it

and fix comment

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

Adjusted Copyright message.

Signed-off-by: Wolfgang Denk <wd@denx.de>
diff --git a/common/Makefile b/common/Makefile
index b9f4ca7..2ca1026 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -155,6 +155,7 @@
 COBJS-$(CONFIG_CMD_KGDB) += kgdb.o
 COBJS-$(CONFIG_LCD) += lcd.o
 COBJS-$(CONFIG_LYNXKDI) += lynxkdi.o
+COBJS-$(CONFIG_MODEM_SUPPORT) += modem.o
 COBJS-$(CONFIG_UPDATE_TFTP) += update.o
 COBJS-$(CONFIG_USB_KEYBOARD) += usb_kbd.o