Patches to support UEFI HTTP Boot IPv4 and IPv6

[Michael Chang]

This patch set enables UEFI HTTP Boot suppot for IPv4 and IPv6. It has been
tested on OVMF virtual machine and several physical servers to work. We would
like to contribute the current work to upstream to get better vision and
support in the future through a much larger community. 

The first two patches came from Aaron Miller <address@hidden> that fixed
the issue of placing IPv6 address in the brackets which is required by the http
message. We hope upstream could review these two patch as well as long as it
has been sent to the mailing list a few months ago.

[PATCH 1/8] misc: fix invalid character recongition in strto*l
[PATCH 2/8] net: read bracketed ipv6 addrs and port numbers

The following three patches came from my previous net_bootp6 patches and are
reworked quite a bit based on latest review. We did the UEFI HTTP Boot based on
these patches in order to get IPv6 support more completed and sharing the
routines for setting up network interface etc.

[PATCH 3/8] bootp: New net_bootp6 command
[PATCH 4/8] efinet: UEFI IPv6 PXE support
[PATCH 5/8] grub.texi: Add net_bootp6 doument

The last three patches are related to UEFI HTTP boot by means of new introduced
URI device path and UEFI protcols used for obtaining the DNS.

[PATCH 6/8] bootp: Add processing DHCPACK packet from HTTP Boot
[PATCH 7/8] efinet: Setting network from UEFI device path
[PATCH 8/8] efinet: Setting DNS server from UEFI protocol

Thanks,
Michael