Standardize bootp, tftpboot, rarpboot, dhcp, and nfs command descriptions

cmd_net.c command descriptions were updated to describe the optional
hostIPaddr argument.  The dhcp command help message was also updated
to more closely reflect the other commands in cmd_net.c

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
Signed-off-by: Ben Warren <biggerbadderben@gmail.com>

common/cmd_net.c

diff --git a/common/cmd_net.c b/common/cmd_net.c
index 79e910c..af691a4 100644
--- a/common/cmd_net.c
+++ b/common/cmd_net.c
@@ -39,8 +39,8 @@
 
 U_BOOT_CMD(
 	bootp,	3,	1,	do_bootp,
-	"bootp\t- boot image via network using BootP/TFTP protocol\n",
-	"[loadAddress] [bootfilename]\n"
+	"bootp\t- boot image via network using BOOTP/TFTP protocol\n",
+	"[loadAddress] [[hostIPaddr:]bootfilename]\n"
 );
 
 int do_tftpb (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
@@ -62,7 +62,7 @@
 U_BOOT_CMD(
 	rarpboot,	3,	1,	do_rarpb,
 	"rarpboot- boot image via network using RARP/TFTP protocol\n",
-	"[loadAddress] [bootfilename]\n"
+	"[loadAddress] [[hostIPaddr:]bootfilename]\n"
 );
 
 #if defined(CONFIG_CMD_DHCP)
@@ -73,8 +73,8 @@
 
 U_BOOT_CMD(
 	dhcp,	3,	1,	do_dhcp,
-	"dhcp\t- invoke DHCP client to obtain IP/boot params\n",
-	"\n"
+	"dhcp\t- boot image via network using DHCP/TFTP protocol\n",
+	"[loadAddress] [[hostIPaddr:]bootfilename]\n"
 );
 #endif