MAINTAINERS: update Geliang's email address

Update my email-address in MAINTAINERS and .mailmap entries to my
kernel.org account.

Suggested-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Geliang Tang <geliang@kernel.org>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

.mailmap

@@ -191,10 +191,11 @@ Gao Xiang <xiang@kernel.org> <gaoxiang25@huawei.com>
 Gao Xiang <xiang@kernel.org> <hsiangkao@aol.com>
 Gao Xiang <xiang@kernel.org> <hsiangkao@linux.alibaba.com>
 Gao Xiang <xiang@kernel.org> <hsiangkao@redhat.com>
-Geliang Tang <geliang.tang@linux.dev> <geliang.tang@suse.com>
-Geliang Tang <geliang.tang@linux.dev> <geliangtang@xiaomi.com>
-Geliang Tang <geliang.tang@linux.dev> <geliangtang@gmail.com>
-Geliang Tang <geliang.tang@linux.dev> <geliangtang@163.com>
+Geliang Tang <geliang@kernel.org> <geliang.tang@linux.dev>
+Geliang Tang <geliang@kernel.org> <geliang.tang@suse.com>
+Geliang Tang <geliang@kernel.org> <geliangtang@xiaomi.com>
+Geliang Tang <geliang@kernel.org> <geliangtang@gmail.com>
+Geliang Tang <geliang@kernel.org> <geliangtang@163.com>
 Georgi Djakov <djakov@kernel.org> <georgi.djakov@linaro.org>
 Gerald Schaefer <gerald.schaefer@linux.ibm.com> <geraldsc@de.ibm.com>
 Gerald Schaefer <gerald.schaefer@linux.ibm.com> <gerald.schaefer@de.ibm.com>

MAINTAINERS

@@ -15324,7 +15324,7 @@ K:	\bmdo_
 NETWORKING [MPTCP]
 M:	Matthieu Baerts <matttbe@kernel.org>
 M:	Mat Martineau <martineau@kernel.org>
-R:	Geliang Tang <geliang.tang@linux.dev>
+R:	Geliang Tang <geliang@kernel.org>
 L:	netdev@vger.kernel.org
 L:	mptcp@lists.linux.dev
 S:	Maintained