xen/arm: Add early printk support for SCIFA compatible UARTs

This patch makes possible to use existing early prink code
for Renesas "Stout" board based on R-Car H2 SoC (SCIFA).

The "EARLY_PRINTK_VERSION" for that board should be 'A':
CONFIG_EARLY_PRINTK=scif,0xe6c40000,A

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Acked-by: Julien Grall <julien.grall@arm.com>

xen/arch/arm/arm32/debug-scif.inc

@@ -1,7 +1,7 @@
 /*
  * xen/arch/arm/arm32/debug-scif.inc
  *
- * SCIF specific debug code
+ * SCIF(A) specific debug code
  *
  * Oleksandr Tyshchenko <oleksandr.tyshchenko@globallogic.com>
  * Copyright (C) 2014, Globallogic.
@@ -22,6 +22,9 @@
 #ifdef EARLY_PRINTK_VERSION_NONE
 #define STATUS_REG    SCIF_SCFSR
 #define TX_FIFO_REG   SCIF_SCFTDR
+#elif EARLY_PRINTK_VERSION_A
+#define STATUS_REG    SCIFA_SCASSR
+#define TX_FIFO_REG   SCIFA_SCAFTDR
 #endif
 
 /*