h8300: Use generic config PREEMPT definition

So that it can handle the new CONFIG_PREEMPT_COUNT.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>

arch/h8300/Kconfig.cpu

@@ -162,9 +162,7 @@ config H8300_TPU_CH
 	int "TPU channel"
 	depends on H8300_TPU
 
-config PREEMPT
-	bool "Preemptible Kernel"
-	default n
+source "kernel/Kconfig.preempt"
 
 source "mm/Kconfig"