net: Remove CONFIG_BOOTP_DHCP_REQUEST_DELAY

This option is not in use anywhere and the documentation implies it's
for some very old and unlikely to be seen currently issues.  Rather than
update the code so the CONFIG symbol could be easily in Kconfig, remove
the code.

Cc: Ramon Fried <rfried.dev@gmail.com>
Signed-off-by: NTom Rini <trini@konsulko.com>
Acked-by: NRamon Fried <rfried.dev@gmail.com>

README

@@ -1173,20 +1173,6 @@ The following options need to be configured:
 
 - DHCP Advanced Options:
 
-		CONFIG_BOOTP_DHCP_REQUEST_DELAY
-
-		A 32bit value in microseconds for a delay between
-		receiving a "DHCP Offer" and sending the "DHCP Request".
-		This fixes a problem with certain DHCP servers that don't
-		respond 100% of the time to a "DHCP request". E.g. On an
-		AT91RM9200 processor running at 180MHz, this delay needed
-		to be *at least* 15,000 usec before a Windows Server 2003
-		DHCP server would reply 100% of the time. I recommend at
-		least 50,000 usec to be safe. The alternative is to hope
-		that one of the retries will be successful but note that
-		the DHCP timeout and retry process takes a longer than
-		this delay.
-
  - Link-local IP address negotiation:
 		Negotiate with other link-local clients on the local network
 		for an address that doesn't require explicit configuration.

net/bootp.c

@@ -1038,9 +1038,6 @@ static void dhcp_send_request_packet(struct bootp_hdr *bp_offer)
 	bcast_ip.s_addr = 0xFFFFFFFFL;
 	net_set_udp_header(iphdr, bcast_ip, PORT_BOOTPS, PORT_BOOTPC, iplen);
 
-#ifdef CONFIG_BOOTP_DHCP_REQUEST_DELAY
-	udelay(CONFIG_BOOTP_DHCP_REQUEST_DELAY);
-#endif	/* CONFIG_BOOTP_DHCP_REQUEST_DELAY */
 	debug("Transmitting DHCPREQUEST packet: len = %d\n", pktlen);
 	net_send_packet(net_tx_packet, pktlen);
 }