x86: Add MultiProcessor (MP) table APIs

The MP table provides a way for the operating system to support
for symmetric multiprocessing as well as symmetric I/O interrupt
handling with the local APIC and I/O APIC. We provide a bunch of
APIs for U-Boot to write the floating table, configuration table
header as well as base and extended table entries.

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

arch/x86/lib/tables.c

@@ -20,6 +20,20 @@ u8 table_compute_checksum(void *v, int len)
 	return checksum;
 }
 
+void table_fill_string(char *dest, const char *src, size_t n, char pad)
+{
+	int start, len;
+	int i;
+
+	strncpy(dest, src, n);
+
+	/* Fill the remaining bytes with pad */
+	len = strlen(src);
+	start = len < n ? len : n;
+	for (i = start; i < n; i++)
+		dest[i] = pad;
+}
+
 void write_tables(void)
 {
 	u32 __maybe_unused rom_table_end = ROM_TABLE_ADDR;