x86: Update SPL for coreboot

At present SPL only works on bare-metal builds. With a few tweaks it can
be used for coreboot also.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/x86/lib/spl.c b/arch/x86/lib/spl.c
index 95a89c0..212b4d5 100644
--- a/arch/x86/lib/spl.c
+++ b/arch/x86/lib/spl.c
@@ -63,7 +63,7 @@
 	 * is not needed. We could make this a CONFIG option or perhaps
 	 * place it immediately below CONFIG_SYS_TEXT_BASE.
 	 */
-	char *ptr = (char *)0x110000;
+	__maybe_unused char *ptr = (char *)0x110000;
 #else
 	struct udevice *punit;
 #endif
@@ -111,7 +111,8 @@
 			      __func__, ret);
 	}
 
-#ifndef CONFIG_TPL
+#ifndef CONFIG_SYS_COREBOOT
+# ifndef CONFIG_TPL
 	memset(&__bss_start, 0, (ulong)&__bss_end - (ulong)&__bss_start);
 
 	/* TODO(sjg@chromium.org): Consider calling cpu_init_r() here */
@@ -140,7 +141,7 @@
 		return ret;
 	}
 	mtrr_commit(true);
-#else
+# else
 	ret = syscon_get_by_driver_data(X86_SYSCON_PUNIT, &punit);
 	if (ret)
 		debug("Could not find PUNIT (err=%d)\n", ret);
@@ -148,6 +149,7 @@
 	ret = set_max_freq();
 	if (ret)
 		debug("Failed to set CPU frequency (err=%d)\n", ret);
+# endif
 #endif
 
 	return 0;
@@ -162,7 +164,7 @@
 		debug("Error %d\n", ret);
 		panic("x86_spl_init fail");
 	}
-#ifdef CONFIG_TPL
+#if IS_ENABLED(CONFIG_TPL) || IS_ENABLED(CONFIG_SYS_COREBOOT)
 	gd->bd = malloc(sizeof(*gd->bd));
 	if (!gd->bd) {
 		printf("Out of memory for bd_info size %x\n", sizeof(*gd->bd));