broadwell: add ROM stage pre console init call back

Serial port on ITE 8772 SuperIO must be initialized before
console_init is called. So the pre console init callback
is added to let mainboard code do proper initialization.

Change-Id: I594e6e4a72f65744deca5cad666eb3b227adeb24
Signed-off-by: Wenkai Du <wenkai.du@intel.com>
Reviewed-on: https://chromium-review.googlesource.com/227933
Reviewed-by: Kenji Chen <kenji.chen@intel.com>
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-by: Rajmohan Mani <rajmohan.mani@intel.com>
Reviewed-by: Shawn Nematbakhsh <shawnn@chromium.org>

src/soc/intel/broadwell/include/soc/romstage.h

@@ -57,4 +57,5 @@ int smbus_read_byte(unsigned device, unsigned address);
 int early_spi_read(u32 offset, u32 size, u8 *buffer);
 int early_spi_read_wpsr(u8 *sr);
 
+void mainboard_pre_console_init(void);
 #endif

src/soc/intel/broadwell/romstage/romstage.c

@@ -59,6 +59,10 @@ void * asmlinkage romstage_main(unsigned long bist,
 	/* PCH Early Initialization */
 	pch_early_init();
 
+	/* Call into mainboard pre console init. Needed to enable serial port
+	   on IT8772 */
+	mainboard_pre_console_init();
+
 	/* Start console drivers */
 	console_init();
 
@@ -149,4 +153,6 @@ int vboot_get_sw_write_protect(void)
 	/* Return unprotected status if status read fails. */
 	return (early_spi_read_wpsr(&status) ? 0 : !!(status & 0x80));
 }
+
+void __attribute__((weak)) mainboard_pre_console_init(void) {}
 #endif