[ARM] Fix HZ definition for OMAP without 32K timer

Unfortunately, OMAP platforms without the 32K timer left HZ set to
an empty value.  Fix this by making the dependency on OMAP_32K_TIMER
rather than OMAP_32K_TIMER_HZ.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/Kconfig

@@ -438,7 +438,7 @@ config HZ
 	int
 	default 128 if ARCH_L7200
 	default 200 if ARCH_EBSA110 || ARCH_S3C2410
-	default OMAP_32K_TIMER_HZ if ARCH_OMAP && OMAP_32K_TIMER_HZ != 0
+	default OMAP_32K_TIMER_HZ if ARCH_OMAP && OMAP_32K_TIMER
 	default 100
 
 config AEABI