mach-snapdragon: enable DM_USB_GADGET by default

This is required for gadget modes to work on most platforms. It must be
disabled for dragonboard410c since that doesn't use dwc3. USB on other
MSM8916 platforms isn't supported by qcom_defconfig anyway.

Link: https://lore.kernel.org/r/20250324-sdm845-fixes-fastboot-v1-3-d177a10f336d@linaro.org
Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index b7311d3..6e234af 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1126,6 +1126,7 @@
 	select SYSRESET_PSCI
 	imply OF_UPSTREAM
 	imply CMD_DM
+	imply DM_USB_GADGET
 
 config ARCH_SOCFPGA
 	bool "Altera SOCFPGA family"
diff --git a/configs/dragonboard410c_defconfig b/configs/dragonboard410c_defconfig
index 967817f..5870aae 100644
--- a/configs/dragonboard410c_defconfig
+++ b/configs/dragonboard410c_defconfig
@@ -60,6 +60,7 @@
 CONFIG_MSM_SERIAL=y
 CONFIG_SPMI_MSM=y
 CONFIG_USB=y
+# CONFIG_DM_USB_GADGET is not set
 CONFIG_USB_EHCI_HCD=y
 CONFIG_USB_EHCI_MSM=y
 CONFIG_USB_ULPI_VIEWPORT=y