[ARM] Fix another use of // as a comment

// disagrees with ld's script parsing ability.  Don't use it.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

include/asm-arm/arch-iop3xx/iop331.h

@@ -42,7 +42,7 @@
 
 /* this can be 128M if OMWTVR1 is set */
 #define IOP331_PCI_MEM_WINDOW_SIZE	0x04000000 /* 64M outbound window */
-//#define IOP331_PCI_MEM_WINDOW_SIZE  (~*IOP331_IALR1 + 1)
+/* #define IOP331_PCI_MEM_WINDOW_SIZE  (~*IOP331_IALR1 + 1) */
 #define IOP331_PCI_LOWER_MEM_PA     0x80000000
 #define IOP331_PCI_LOWER_MEM_BA     (*IOP331_OMWTVR0)
 #define IOP331_PCI_UPPER_MEM_PA     (IOP331_PCI_LOWER_MEM_PA + IOP331_PCI_MEM_WINDOW_SIZE - 1)