OMAP3: AM3505/3517 do not have IO wakeup capability

AM3505/3517 doesn't have IO wakeup capability, so we do not need to set
the bit OMAP3430_EN_IO and the bit OMAP3430_EN_IO_CHAIN in the register
PM_WKEN_WKUP when the system enters suspend state.

Tested on AM3517EVM and OMAP3530EVM.

Signed-off-by: Stanley.Miao <stanley.miao@windriver.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>