x86: quark: Lock HMBOUND register before jumping to kernel

When Linux kernel boots, it hangs at:

[    0.829408] Intel Quark side-band driver registered

This happens when Quark kernel Isolated Memory Region (IMR) driver
tries to lock an IMR register to protect kernel's text and rodata
sections. However in order to have IMR function correctly, HMBOUND
register must be locked otherwise the system just hangs.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>

arch/x86/cpu/quark/quark.c

@@ -288,5 +288,8 @@ void board_final_cleanup(void)
 	val &= ~0xff0000;
 	writel(val, &rcba->esd);
 
+	/* Lock HMBOUND for security */
+	msg_port_setbits(MSG_PORT_HOST_BRIDGE, HM_BOUND, HM_BOUND_LOCK);
+
 	return;
 }

arch/x86/include/asm/arch-quark/quark.h

@@ -32,6 +32,7 @@
 
 /* Host Memory I/O Boundary */
 #define HM_BOUND		0x08
+#define HM_BOUND_LOCK		0x00000001
 
 /* Extended Configuration Space */
 #define HEC_REG			0x09