ARM: OMAP1: call platform_device_put() in error case in omap1_dm_timer_init()

If platform_device_add() is not called or failed, it should call
platform_device_put() in error case.

Fixes: 97933d6c ("ARM: OMAP1: dmtimer: conversion to platform devices")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Message-Id: <20220701094602.2365099-1-yangyingliang@huawei.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>