cpufreq: blackfin: enable driver for CONFIG_BFIN_CPU_FREQ

By mistake blackfin's cpufreq driver is enabled when CONFIG_BLACKFIN was
present, whereas it should have been enabled only when CONFIG_BFIN_CPU_FREQ is
present.

Fix it.
Acked-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

drivers/cpufreq/Makefile

@@ -83,7 +83,7 @@ obj-$(CONFIG_CPU_FREQ_MAPLE)		+= maple-cpufreq.o
 ##################################################################################
 # Other platform drivers
 obj-$(CONFIG_AVR32_AT32AP_CPUFREQ)	+= at32ap-cpufreq.o
-obj-$(CONFIG_BLACKFIN)			+= blackfin-cpufreq.o
+obj-$(CONFIG_BFIN_CPU_FREQ)		+= blackfin-cpufreq.o
 obj-$(CONFIG_CRIS_MACH_ARTPEC3)		+= cris-artpec3-cpufreq.o
 obj-$(CONFIG_ETRAXFS)			+= cris-etraxfs-cpufreq.o
 obj-$(CONFIG_IA64_ACPI_CPUFREQ)		+= ia64-acpi-cpufreq.o