pinctrl: msm: Add ps_hold function in pinctrl-apq8064 binding documentation

This adds a function ps_hold (Power Suppy Hold Signal) in pinctrl-ap8064
documentation which was missing. This function is used to reset the targets
with apq8064 soc.

CC: "Ivan T. Ivanov" <iivanov@mm-sol.com>
CC: Stephen Boyd <sboyd@codeaurora.org>
CC: Andy Gross <agross@codeaurora.org>
Acked-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Signed-off-by: Pramod Gurav <pramod.gurav@smartplayin.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/pinctrl/qcom,apq8064-pinctrl.txt

@@ -50,7 +50,7 @@ Valid values for function are:
   gsbi4_cam_i2c, gsbi5, gsbi5_spi_cs1, gsbi5_spi_cs2, gsbi5_spi_cs3, gsbi6,
   gsbi6_spi_cs1, gsbi6_spi_cs2, gsbi6_spi_cs3, gsbi7, gsbi7_spi_cs1,
   gsbi7_spi_cs2, gsbi7_spi_cs3, gsbi_cam_i2c, hdmi, mi2s, riva_bt, riva_fm,
-  riva_wlan, sdc2, sdc4, slimbus, spkr_i2s, tsif1, tsif2, usb2_hsic,
+  riva_wlan, sdc2, sdc4, slimbus, spkr_i2s, tsif1, tsif2, usb2_hsic, ps_hold
 
 Example: