PXA: cleanup vpac270 config and set CONFIG_SYS_HZ to 1000

* CONFIG_SYS_CLKS_IN_HZ is not used anywhere, so removing it
* CONFIG_SYS_HZ is set to 1000 on most architectures, so it
  seems to be the safe default
Signed-off-by: Mikhail Kshevetskiy <mikhail.kshevetskiy@gmail.com>

include/configs/vpac270.h

@@ -146,8 +146,7 @@
 /*
  * Clock Configuration
  */
-#undef	CONFIG_SYS_CLKS_IN_HZ
-#define	CONFIG_SYS_HZ			3250000		/* Timer @ 3250000 Hz */
+#define	CONFIG_SYS_HZ			1000		/* Timer @ 3250000 Hz */
 #define	CONFIG_SYS_CPUSPEED		0x190		/* 312MHz */
 
 /*