soc/ite/ec: it51xxx: Add condition to select the mode based on CONFIG_ESPI

If CONFIG_ESPI is defined, use 0xA4 (eSPI mode).
Otherwise, use 0xA5 (LPC mode).

Signed-off-by: Tim Lin <tim2.lin@ite.corp-partner.google.com>

Author: GTLin08

soc/ite/ec/it51xxx/vector.S

@@ -49,8 +49,11 @@ SECTION_FUNC(vectors, __start)
 .global eflash_sig
 eflash_sig:
 .byte 0xA5, 0xA5, 0xA5, 0xA5, 0xA5, 0xA5
-/* Enable eSPI */
-.byte 0xA4
+#ifdef CONFIG_ESPI
+.byte 0xA4 /* eSPI mode */
+#else
+.byte 0xA5 /* LPC mode */
+#endif
 /* Flag of signature. Enable internal clock generator */
 .byte 0xB4
 .byte 0x85, 0x12, 0x5A, 0x5A, 0xAA, 0xAA, 0x55, 0x55