ARM: shmobile: Fix is_e2 warning

Fix "is_e2" warning introduced by:

9ce3fa68 ARM: shmobile: rcar-gen2: Add CA7 arch_timer initialization for r8a7794

Only triggers on kernel configurations that have ARCH_ARM_TIMER=n.
Signed-off-by: Magnus Damm <damm+renesas@opensource.se>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/mach-shmobile/setup-rcar-gen2.c

@@ -52,15 +52,13 @@ void __init rcar_gen2_timer_init(void)
 {
 #if defined(CONFIG_ARM_ARCH_TIMER) || defined(CONFIG_COMMON_CLK)
 	u32 mode = rcar_gen2_read_mode_pins();
-	bool is_e2 = (bool)of_find_compatible_node(NULL, NULL,
-		"renesas,r8a7794");
 #endif
 #ifdef CONFIG_ARM_ARCH_TIMER
 	void __iomem *base;
 	int extal_mhz = 0;
 	u32 freq;
 
-	if (is_e2) {
+	if (of_machine_is_compatible("renesas,r8a7794")) {
 		freq = 260000000 / 8;	/* ZS / 8 */
 		/* CNTVOFF has to be initialized either from non-secure
 		 * Hypervisor mode or secure Monitor mode with SCR.NS==1.