cpufreq: make DB8500 cpufreq driver compile

Concluding interface update and movement of the driver by making
the DB8500 cpufreq driver compile in the cpufreq subsystem.

Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: Dave Jones <davej@redhat.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/cpufreq/Makefile

@@ -39,3 +39,5 @@ obj-$(CONFIG_X86_CPUFREQ_NFORCE2)	+= cpufreq-nforce2.o
 
 ##################################################################################d
 
+# ARM SoC drivers
+obj-$(CONFIG_UX500_SOC_DB8500)		+= db8500-cpufreq.o