ACPI/IORT: Fix memory leak in iort_rmr_alloc_sids()

ACPI/IORT: Fix memory leak in iort_rmr_alloc_sids()

If krealloc_array() fails in iort_rmr_alloc_sids(), the function returns
NULL but does not free the original 'sids' allocation. This results in a
memory leak since the caller overwrites the original pointer with the
NULL return value.

Fixes: 491cf4a6735a ("ACPI/IORT: Add support to retrieve IORT RMR reserved regions")
Cc: <stable@vger.kernel.org> # 6.0.x
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Link: https://lore.kernel.org/r/20250828112243.61460-1-linmq006@gmail.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>