clocksource/drivers/lpc32xx: Support timer-based ARM delay

This commit implements the ARM timer-based delay timer for the
LPC32xx, LPC18xx, LPC43xx family of SoCs.

Also, add a dependency to restrict compiling this driver for
the ARM architecture.

Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Joachim Eastwood <manabian@gmail.com>
Tested-by: Joachim Eastwood <manabian@gmail.com>
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 56777f0..c9c4db6 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -153,6 +153,7 @@
 config CLKSRC_LPC32XX
 	bool "Clocksource for LPC32XX" if COMPILE_TEST
 	depends on GENERIC_CLOCKEVENTS && HAS_IOMEM
+	depends on ARM
 	select CLKSRC_MMIO
 	select CLKSRC_OF
 	help