RDMA/siw: Change maintainer email address

Change siw maintainer email address since old address
will become disfunctional. Also add info to .mailmap

Signed-off-by: Bernard Metzler <bernard.metzler@linux.dev>
Link: https://patch.msgid.link/20250723132107.2188-1-bernard.metzler@linux.dev
Signed-off-by: Leon Romanovsky <leon@kernel.org>

Author: BernardMetzler

.mailmap

@@ -138,6 +138,7 @@ Benjamin Poirier <benjamin.poirier@gmail.com> <bpoirier@suse.de>
 Benjamin Tissoires <bentiss@kernel.org> <benjamin.tissoires@gmail.com>
 Benjamin Tissoires <bentiss@kernel.org> <benjamin.tissoires@redhat.com>
 Benno Lossin <lossin@kernel.org> <benno.lossin@proton.me>
+Bernard Metzler <bernard.metzler@linux.dev> <bmt@zurich.ibm.com>
 Bingwu Zhang <xtex@aosc.io> <xtexchooser@duck.com>
 Bingwu Zhang <xtex@aosc.io> <xtex@xtexx.eu.org>
 Bjorn Andersson <andersson@kernel.org> <bjorn@kryo.se>

MAINTAINERS

@@ -22955,7 +22955,7 @@ S:	Maintained
 F:	drivers/leds/leds-net48xx.c
 
 SOFT-IWARP DRIVER (siw)
-M:	Bernard Metzler <bmt@zurich.ibm.com>
+M:	Bernard Metzler <bernard.metzler@linux.dev>
 L:	linux-rdma@vger.kernel.org
 S:	Supported
 F:	drivers/infiniband/sw/siw/