MAINTAINERS: add Usama as a THP reviewer

MAINTAINERS: add Usama as a THP reviewer

Usama has been active around THP, really enjoys working on THPs, and tries
to review all the patches that come in.

Let's invite him to the THP party as a reviewer to help with the ongoing
THP review load.

Link: https://lore.kernel.org/20260702140257.44780-1-lance.yang@linux.dev
Signed-off-by: Lance Yang <lance.yang@linux.dev>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Lorenzo Stoakes <ljs@kernel.org>
Acked-by: Zi Yan <ziy@nvidia.com>
Acked-by: Barry Song <baohua@kernel.org>
Acked-by: SJ Park <sj@kernel.org>
Acked-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>