arm: pxa: config option for PXA270 turbo mode

PXA270 CPU has turbo mode. The mode is 2.5 times faster than the
default run mode. Activating the mode early significantly speeds
up boot process.
Signed-off-by: NSergey Yanovich <ynvich@gmail.com>

arch/arm/cpu/pxa/pxa2xx.c

@@ -244,7 +244,7 @@ void pxa_clock_setup(void)
 {
 	writel(CONFIG_SYS_CKEN, CKEN);
 	writel(CONFIG_SYS_CCCR, CCCR);
-	asm volatile("mcr	p14, 0, %0, c6, c0, 0" : : "r"(2));
+	asm volatile("mcr	p14, 0, %0, c6, c0, 0" : : "r"(0x0b));
 
 	/* enable the 32Khz oscillator for RTC and PowerManager */
 	writel(OSCC_OON, OSCC);