NetworkPkg: DnsDxe: fix return type of DnsFillinQNameForQueryIp()

NetworkPkg: DnsDxe: fix return type of DnsFillinQNameForQueryIp()

Change the return type of DnsFillinQNameForQueryIp() from (UINT8*) to
(CHAR*). This brings the function in sync with both its internal variables
and all of its call sites, fixing the following gcc build breakage:

> NetworkPkg/DnsDxe/DnsImpl.c: In function 'DnsFillinQNameForQueryIp':
> NetworkPkg/DnsDxe/DnsImpl.c:1068:3: error: pointer targets in return
>                                     differ in signedness
>                                     [-Werror=pointer-sign]
>    return QueryName;
>    ^

The code was added in git commit fcae1a99 (SVN r19579).

Cc: Subramanian Sriram <sriram-s@hpe.com>
Cc: El-Haj-Mahmoud Samer <samer.el-haj-mahmoud@hpe.com>
Cc: Ye Ting <ting.ye@intel.com>
Cc: Fu Siyuan <siyuan.fu@intel.com>
Cc: Jiaxin Wu <jiaxin.wu@intel.com>
Cc: Ye Ting <ting.ye@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jiaxin Wu <jiaxin.wu@intel.com>
Reviewed-by: Fu Siyuan <siyuan.fu@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19609 6f19259b-4bc3-4df7-8a09-765794883524