powerpc/mpc5200: Document and tidy irq driver

This patch adds documentation to the mpc5200 interrupt controller
driver and cleans up some minor coding conventions.  It also moves the
contents of mpc52xx_pic.h into the driver proper (except for a small
common bit that is moved to the common mpc52xx.h) because the
information encoded there is not required by any other part of kernel
code.  Finally for code readability sake, the L2_OFFSET shift value
is removed because the code using it resolves to a noop.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/arch/powerpc/include/asm/mpc52xx.h b/arch/powerpc/include/asm/mpc52xx.h
index 81ef10b..81a2393 100644
--- a/arch/powerpc/include/asm/mpc52xx.h
+++ b/arch/powerpc/include/asm/mpc52xx.h
@@ -239,6 +239,25 @@
 	u16 mclken_div_psc6;	/* CDM + 0x36  reg13 byte2,3 */
 };
 
+/* Interrupt controller Register set */
+struct mpc52xx_intr {
+	u32 per_mask;		/* INTR + 0x00 */
+	u32 per_pri1;		/* INTR + 0x04 */
+	u32 per_pri2;		/* INTR + 0x08 */
+	u32 per_pri3;		/* INTR + 0x0c */
+	u32 ctrl;		/* INTR + 0x10 */
+	u32 main_mask;		/* INTR + 0x14 */
+	u32 main_pri1;		/* INTR + 0x18 */
+	u32 main_pri2;		/* INTR + 0x1c */
+	u32 reserved1;		/* INTR + 0x20 */
+	u32 enc_status;		/* INTR + 0x24 */
+	u32 crit_status;	/* INTR + 0x28 */
+	u32 main_status;	/* INTR + 0x2c */
+	u32 per_status;		/* INTR + 0x30 */
+	u32 reserved2;		/* INTR + 0x34 */
+	u32 per_error;		/* INTR + 0x38 */
+};
+
 #endif /* __ASSEMBLY__ */