pwm: Move Blackfin PWM driver to PWM framework

This commit moves the Blackfin PWM driver to the drivers/pwm sub-
directory and converts it to register with the new PWM framework.

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

drivers/pwm/Makefile

@@ -1,2 +1,3 @@
 obj-$(CONFIG_PWM)		+= core.o
+obj-$(CONFIG_PWM_BFIN)		+= pwm-bfin.o
 obj-$(CONFIG_PWM_TEGRA)		+= pwm-tegra.o