ACPI: ARM64: add acpi_iort.h to MAINTAINERS

IORT(Input Output Remapping Table) represents the I/O topology of an
Arm-based system for use with the ACPI, so acpi_iort.h is for arm64
only.

This helps git-send-email to figure out the proper maintainers when
touching the file.
Signed-off-by: Hanjun Guo <guohanjun@huawei.com>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Link: https://lore.kernel.org/r/20240808130946.1028376-1-guohanjun@huawei.comSigned-off-by: Will Deacon <will@kernel.org>

MAINTAINERS

@@ -334,6 +334,7 @@ L:	linux-acpi@vger.kernel.org
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
 S:	Maintained
 F:	drivers/acpi/arm64
+F:	include/linux/acpi_iort.h
 
 ACPI FOR RISC-V (ACPI/riscv)
 M:	Sunil V L <sunilvl@ventanamicro.com>