acpi: Move acpi_write_tables() to a generic header

This function is used by both x86 and sandbox. Put it in a common header
file.

Signed-off-by: Simon Glass <sjg@chromium.org>

arch/sandbox/include/asm/acpi_table.h

@@ -6,6 +6,6 @@
 #ifndef __ASM_ACPI_TABLE_H__
 #define __ASM_ACPI_TABLE_H__
 
-ulong write_acpi_tables(ulong start);
+/* Empty for now, this file is required by acpi/acpi_table.h */
 
 #endif /* __ASM_ACPI_TABLE_H__ */

arch/x86/include/asm/acpi_table.h

@@ -64,8 +64,6 @@ int acpi_write_dbg2_pci_uart(struct acpi_ctx *ctx, struct udevice *dev,
  */
 int acpi_create_gnvs(struct acpi_global_nvs *gnvs);
 
-ulong write_acpi_tables(ulong start);
-
 /**
  * acpi_get_rsdp_addr() - get ACPI RSDP table address
  *