x86: acpi: Remove header length check when writing tables

Before moving 'current' pointer during ACPI table writing, we always
check the table length to see if it is larger than the table header.
Since our purpose is to generate valid tables, the check logic is
always true, which can be avoided.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/x86/lib/acpi_table.c b/arch/x86/lib/acpi_table.c
index 1c57094..ffb4678 100644
--- a/arch/x86/lib/acpi_table.c
+++ b/arch/x86/lib/acpi_table.c
@@ -376,13 +376,11 @@
 	debug("ACPI:    * DSDT\n");
 	dsdt = (struct acpi_table_header *)current;
 	memcpy(dsdt, &AmlCode, sizeof(struct acpi_table_header));
-	if (dsdt->length >= sizeof(struct acpi_table_header)) {
-		current += sizeof(struct acpi_table_header);
-		memcpy((char *)current,
-			(char *)&AmlCode + sizeof(struct acpi_table_header),
-			dsdt->length - sizeof(struct acpi_table_header));
-		current += dsdt->length - sizeof(struct acpi_table_header);
-	}
+	current += sizeof(struct acpi_table_header);
+	memcpy((char *)current,
+	       (char *)&AmlCode + sizeof(struct acpi_table_header),
+	       dsdt->length - sizeof(struct acpi_table_header));
+	current += dsdt->length - sizeof(struct acpi_table_header);
 	current = ALIGN(current, 16);
 
 	debug("ACPI:    * FADT\n");
@@ -395,20 +393,16 @@
 	debug("ACPI:    * MADT\n");
 	madt = (struct acpi_madt *)current;
 	acpi_create_madt(madt);
-	if (madt->header.length > sizeof(struct acpi_madt)) {
-		current += madt->header.length;
-		acpi_add_table(rsdp, madt);
-	}
+	current += madt->header.length;
+	acpi_add_table(rsdp, madt);
 	current = ALIGN(current, 16);
 
 	debug("ACPI:    * MCFG\n");
 	mcfg = (struct acpi_mcfg *)current;
 	acpi_create_mcfg(mcfg);
-	if (mcfg->header.length > sizeof(struct acpi_mcfg)) {
-		current += mcfg->header.length;
-		current = ALIGN(current, 16);
-		acpi_add_table(rsdp, mcfg);
-	}
+	current += mcfg->header.length;
+	acpi_add_table(rsdp, mcfg);
+	current = ALIGN(current, 16);
 
 	debug("current = %x\n", current);