acpi: Add missing ARM acpi_table header

The pci_mmc.c driver can generate ACPI info and therefore includes
asm/acpi_table.h by proxy. This file does not exist for the ARM
architecture and thus code compilation failed when using this
driver on ARM.

Signed-off-by: Harm Berntsen <harm.berntsen@nedap.com>
CC: Simon Glass <sjg@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>