[SERIAL] Fix status reporting with PL011 serial driver

The receiver status register reports latched error conditions, which
must be cleared by writing to it.  However, the data register reports
unlatched conditions which are associated with the current character.
Use the data register to interpret error status rather than the RSR.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/include/asm-arm/hardware/amba_serial.h b/include/asm-arm/hardware/amba_serial.h
index 71770aa..dc726ff 100644
--- a/include/asm-arm/hardware/amba_serial.h
+++ b/include/asm-arm/hardware/amba_serial.h
@@ -50,6 +50,11 @@
 #define UART011_ICR		0x44	/* Interrupt clear register. */
 #define UART011_DMACR		0x48	/* DMA control register. */
 
+#define UART011_DR_OE		(1 << 11)
+#define UART011_DR_BE		(1 << 10)
+#define UART011_DR_PE		(1 << 9)
+#define UART011_DR_FE		(1 << 8)
+
 #define UART01x_RSR_OE 		0x08
 #define UART01x_RSR_BE 		0x04
 #define UART01x_RSR_PE 		0x02