linux: fix depmod location after move to host-kmod

The host-kmod version of depmod gets installed into HOST_DIR/sbin, so
adjust the path we use to refer to it in linux.mk

Reported-by: Ryan Coe <bluemrp9@gmail.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

linux/linux.mk

@@ -47,7 +47,7 @@ LINUX_MAKE_FLAGS = \
 	ARCH=$(KERNEL_ARCH) \
 	INSTALL_MOD_PATH=$(TARGET_DIR) \
 	CROSS_COMPILE="$(CCACHE) $(TARGET_CROSS)" \
-	DEPMOD=$(HOST_DIR)/usr/sbin/depmod
+	DEPMOD=$(HOST_DIR)/sbin/depmod
 
 # Get the real Linux version, which tells us where kernel modules are
 # going to be installed in the target filesystem.