ramips: rename pwm kernel module

With kernel 4.14 the OpenWrt specific module name collides with the
upstream added module for Mediatek ARM Socs.

During addition of preliminary support for kernel 4.14, the config
symbol used by the out of tree driver was already renamed but the ramips
kernel package wasn't updated.

Fix the build error by updating the config and kernel module name for
the kernel package.

Signed-off-by: Mathias Kresin <dev@kresin.me>

target/linux/ramips/modules.mk

@@ -7,24 +7,24 @@
 
 OTHER_MENU:=Other modules
 
-define KernelPackage/pwm-mediatek
+define KernelPackage/pwm-mediatek-ramips
   SUBMENU:=Other modules
   TITLE:=MT7628 PWM
   DEPENDS:=@(TARGET_ramips_mt76x8)
   KCONFIG:= \
 	CONFIG_PWM=y \
-	CONFIG_PWM_MEDIATEK \
+	CONFIG_PWM_MEDIATEK_RAMIPS \
 	CONFIG_PWM_SYSFS=y
   FILES:= \
-	$(LINUX_DIR)/drivers/pwm/pwm-mediatek.ko
-  AUTOLOAD:=$(call AutoProbe,pwm-mediatek)
+	$(LINUX_DIR)/drivers/pwm/pwm-mediatek-ramips.ko
+  AUTOLOAD:=$(call AutoProbe,pwm-mediatek-ramips)
 endef
 
 define KernelPackage/pwm-mediatek/description
   Kernel modules for MediaTek Pulse Width Modulator
 endef
 
-$(eval $(call KernelPackage,pwm-mediatek))
+$(eval $(call KernelPackage,pwm-mediatek-ramips))
 
 define KernelPackage/sdhci-mt7620
   SUBMENU:=Other modules