mini2440 beer(pwm) 驱动

mini2440beer（通常称pwm或timer）驱动，注册为misc（杂项）设备，挂载再platformbus上，测试信息：U-Boot2012.07(Aug302012-21:55:43)++++++++++++++++++++++++++++++++++++++++++++++++++++++++++Welcometomyu-boot++++++Liyong-zou+++++++++++++++++++++++++++++++++++++++++++++++++++++++