staging: rtl8723bs: fix a potential memory leak in rtw_init_cmd_priv()

In the Linux kernel, the following vulnerability has been resolved:

staging: rtl8723bs: fix a potential memory leak in rtw_init_cmd_priv()

In rtw_init_cmd_priv(), if pcmdpriv->rsp_allocated_buf is allocated in failure, then pcmdpriv->cmd_allocated_buf will be not properly released. Besides, considering there are only two error paths and the first one can directly return, so we do not need implicitly jump to the exit tag to execute the error handler.

So this patch added kfree(pcmdpriv->cmd_allocated_buf); on the error path to release the resource and simplified the return logic of rtw_init_cmd_priv(). As there is no proper device to test with, no runtime testing was performed.