clk: remove duplicated COMMON_CLK_NXP record from clk/Kconfig

Presumably the second COMMON_CLK_NXP config option in
drivers/clk/Kconfig appeared after a merge conflict resolution, remove
the wrong record of two.
Signed-off-by: NVladimir Zapolskiy <vz@mleia.com>
Signed-off-by: NMichael Turquette <mturquette@baylibre.com>

drivers/clk/Kconfig

@@ -187,11 +187,6 @@ config COMMON_CLK_PWM
 	  Adapter driver so that any PWM output can be (mis)used as clock signal
 	  at 50% duty cycle.
 
-config COMMON_CLK_NXP
-	def_bool COMMON_CLK && ARCH_LPC18XX
-	---help---
-	  Support for clock providers on NXP platforms.
-
 config COMMON_CLK_PXA
 	def_bool COMMON_CLK && ARCH_PXA
 	---help---