mach-snapdragon: switch to PMIC button driver

The PMIC button driver is a much better representation of the hardware
here, adjust the boards to use upstream DT and the PMIC button driver
instead of exposing the buttons as GPIOs and relying on the GPIO-button
driver.

Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>
diff --git a/arch/arm/mach-snapdragon/Kconfig b/arch/arm/mach-snapdragon/Kconfig
index 3c9f3be..ad66710 100644
--- a/arch/arm/mach-snapdragon/Kconfig
+++ b/arch/arm/mach-snapdragon/Kconfig
@@ -17,6 +17,7 @@
 	select LINUX_KERNEL_IMAGE_HEADER
 	imply CLK_QCOM_SDM845
 	imply PINCTRL_QCOM_SDM845
+	imply BUTTON_QCOM_PMIC
 
 config LNX_KRNL_IMG_TEXT_OFFSET_BASE
 	default 0x80000000
@@ -30,6 +31,7 @@
 	select ENABLE_ARM_SOC_BOOT0_HOOK
 	imply CLK_QCOM_APQ8016
 	imply PINCTRL_QCOM_APQ8016
+	imply BUTTON_QCOM_PMIC
 	help
 	  Support for 96Boards Dragonboard 410C. This board complies with
 	  96Board Open Platform Specifications. Features:
@@ -45,6 +47,7 @@
 	bool "96Boards Dragonboard 820C"
 	imply CLK_QCOM_APQ8096
 	imply PINCTRL_QCOM_APQ8096
+	imply BUTTON_QCOM_PMIC
 	help
 	  Support for 96Boards Dragonboard 820C. This board complies with
 	  96Board Open Platform Specifications. Features: