ARM: OMAP4: PM: OMAP4 Power Domain Porting Related Clean-up.

Module offsets were same for OMAP2 and OMAP3 while they differ for OMAP4.
Hence we need different macros for identifying platform specific offsets.

Signed-off-by: Abhijit Pagare <abhijitpagare@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Rajendra Nayak <rnayak@ti.com>

arch/arm/mach-omap2/pm24xx.c

@@ -219,11 +219,12 @@ static void omap2_enter_mpu_retention(void)
 		/* Try to enter MPU retention */
 		prm_write_mod_reg((0x01 << OMAP_POWERSTATE_SHIFT) |
 				  OMAP_LOGICRETSTATE,
-				  MPU_MOD, PM_PWSTCTRL);
+				  MPU_MOD, OMAP2_PM_PWSTCTRL);
 	} else {
 		/* Block MPU retention */
 
-		prm_write_mod_reg(OMAP_LOGICRETSTATE, MPU_MOD, PM_PWSTCTRL);
+		prm_write_mod_reg(OMAP_LOGICRETSTATE, MPU_MOD,
+						 OMAP2_PM_PWSTCTRL);
 		only_idle = 1;
 	}