x86: zImage: Propagate acpi_rsdp_addr to kernel via boot parameters

New field acpi_rsdp_addr, which has been introduced in boot protocol
v2.14 [1], in boot parameters tells kernel the exact address of RDSP
ACPI table. Knowing it increases robustness of the kernel by avoiding
in some cases traversal through a part of physical memory.
It will slightly reduce boot time by the same reason.

[1] See Linux kernel commit

  2f74cbf ("x86/boot: Add the ACPI RSDP address to struct setup_header::acpi_rdsp_addr")
  @ https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=2f74cbf

for the details.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
[bmeng: updated the kernel commit git URL and fixed one style issue]
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/x86/lib/zimage.c b/arch/x86/lib/zimage.c
index d224db4..eae2663 100644
--- a/arch/x86/lib/zimage.c
+++ b/arch/x86/lib/zimage.c
@@ -24,6 +24,7 @@
 #include <asm/arch/timestamp.h>
 #endif
 #include <linux/compiler.h>
+#include "acpi_table.h"
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -255,6 +256,11 @@
 		hdr->hardware_subarch = X86_SUBARCH_INTEL_MID;
 #endif
 
+#ifdef CONFIG_GENERATE_ACPI_TABLE
+	if (bootproto >= 0x020e)
+		hdr->acpi_rsdp_addr = acpi_rsdp_addr;
+#endif
+
 	setup_video(&setup_base->screen_info);
 
 	return 0;