ARM: OMAP2+: serial: Change MAX_HSUART_PORTS to 6

Extends the maximum number of UART ports to 6 from 4 because AM335X
device have six UART ports.
Signed-off-by: AnilKumar Ch <anilkumar@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/plat-omap/include/plat/omap-serial.h

@@ -52,7 +52,7 @@
 
 #define OMAP_UART_DMA_CH_FREE	-1
 
-#define OMAP_MAX_HSUART_PORTS	4
+#define OMAP_MAX_HSUART_PORTS	6
 
 #define MSR_SAVE_FLAGS		UART_MSR_ANY_DELTA