hv:Reshuffle console/uart code

The current hierarchy :
  CONSOLE --> SERIAL -->UART DRIVER
This patch remove SERIAL layer, that is console will
call UART driver directly, change it to:
  CONSOLE  --> UART DRIVER
Remove some related data structures and registration and callback.
Cleanup vuart.c

Signed-off-by: Mingqiang Chi <mingqiang.chi@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>

hypervisor/arch/x86/cpu.c

@@ -478,9 +478,6 @@ static void bsp_boot_post(void)
 	/* Perform any necessary BSP initialization */
 	init_bsp();
 
-	/* Initialize Serial */
-	serial_init();
-
 	/* Initialize console */
 	console_init();