OMAP3: PM: fix IO daisy chain enable to use PM_WKEN reg

Checking to se if the IO daisy chain is enabled should be checking the
PM_WKEN register, not the PM_WKST register.  Reading PM_WKST tells us
if an event occurred, not whether or not it is enabled.

Apparently, we've been lucky until now in that a pending event has not
been there during enable.  However, on 3630/Zoom3, I noticed because
of the WARN that this timeout was always happening.
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/pm34xx.c

@@ -99,7 +99,7 @@ static void omap3_enable_io_chain(void)
 		/* Do a readback to assure write has been done */
 		prm_read_mod_reg(WKUP_MOD, PM_WKEN);
 
-		while (!(prm_read_mod_reg(WKUP_MOD, PM_WKST) &
+		while (!(prm_read_mod_reg(WKUP_MOD, PM_WKEN) &
 			 OMAP3430_ST_IO_CHAIN_MASK)) {
 			timeout++;
 			if (timeout > 1000) {
@@ -108,7 +108,7 @@ static void omap3_enable_io_chain(void)
 				return;
 			}
 			prm_set_mod_reg_bits(OMAP3430_ST_IO_CHAIN_MASK,
-					     WKUP_MOD, PM_WKST);
+					     WKUP_MOD, PM_WKEN);
 		}
 	}
 }