ARM/dts: OMAP3: fix pinctrl-single configuration

 - Fix 'function-mask' referring to TRM (Omap 36xx) Section 13.4.4:
   "Pad Functional Multiplexing and Configuration".
 - Fix 'omap3_pmx_wkup' referring to TRM Table 13-6:
   "Wkup Control Module Pad Configuration Register Fields".

Note that these fixes are not critical currently as we
are not yet using the missing range of pinmux registers
at this point.

Signed-off-by: Christoph Fritz <chf.fritz@googlemail.com>
[tony@atomide.com: updated comments]
Signed-off-by: Tony Lindgren <tony@atomide.com>