MAINTAINERS: update Naoya Horiguchi's email address

My old NEC address has been removed, so update MAINTAINERS and .mailmap to
map it to my gmail address.

Link: https://lkml.kernel.org/r/20240412181720.18452-1-nao.horiguchi@gmail.com
Signed-off-by: Naoya Horiguchi <nao.horiguchi@gmail.com>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

.mailmap

@@ -446,7 +446,8 @@ Mythri P K <mythripk@ti.com>
 Nadav Amit <nadav.amit@gmail.com> <namit@vmware.com>
 Nadav Amit <nadav.amit@gmail.com> <namit@cs.technion.ac.il>
 Nadia Yvette Chambers <nyc@holomorphy.com> William Lee Irwin III <wli@holomorphy.com>
-Naoya Horiguchi <naoya.horiguchi@nec.com> <n-horiguchi@ah.jp.nec.com>
+Naoya Horiguchi <nao.horiguchi@gmail.com> <n-horiguchi@ah.jp.nec.com>
+Naoya Horiguchi <nao.horiguchi@gmail.com> <naoya.horiguchi@nec.com>
 Nathan Chancellor <nathan@kernel.org> <natechancellor@gmail.com>
 Neeraj Upadhyay <quic_neeraju@quicinc.com> <neeraju@codeaurora.org>
 Neil Armstrong <neil.armstrong@linaro.org> <narmstrong@baylibre.com>

MAINTAINERS

@@ -10024,7 +10024,7 @@ F:	drivers/media/platform/st/sti/hva
 
 HWPOISON MEMORY FAILURE HANDLING
 M:	Miaohe Lin <linmiaohe@huawei.com>
-R:	Naoya Horiguchi <naoya.horiguchi@nec.com>
+R:	Naoya Horiguchi <nao.horiguchi@gmail.com>
 L:	linux-mm@kvack.org
 S:	Maintained
 F:	mm/hwpoison-inject.c