microblaze: trivial: Add comment for AXI pvr

#define PVR1_USER2_MASK			0xFFFFFFFF

/* Configuration PVR masks */

#define PVR2_D_OPB_MASK			0x80000000

#define PVR2_D_OPB_MASK			0x80000000 /* or AXI */

#define PVR2_D_LMB_MASK			0x40000000

#define PVR2_I_OPB_MASK			0x20000000

#define PVR2_I_OPB_MASK			0x20000000 /* or AXI */

#define PVR2_I_LMB_MASK			0x10000000

#define PVR2_INTERRUPT_IS_EDGE_MASK	0x08000000

#define PVR2_EDGE_IS_POSITIVE_MASK	0x04000000

#define PVR2_OPCODE_0x0_ILL_MASK	0x00000040

#define PVR2_UNALIGNED_EXC_MASK		0x00000020

#define PVR2_ILL_OPCODE_EXC_MASK	0x00000010

#define PVR2_IOPB_BUS_EXC_MASK		0x00000008

#define PVR2_DOPB_BUS_EXC_MASK		0x00000004

#define PVR2_IOPB_BUS_EXC_MASK		0x00000008 /* or AXI */

#define PVR2_DOPB_BUS_EXC_MASK		0x00000004 /* or AXI */

#define PVR2_DIV_ZERO_EXC_MASK		0x00000002

#define PVR2_FPU_EXC_MASK		0x00000001