CVE-2023-53458 media: cx23885: Fix a null-ptr-deref bug in buffer_prepare() and buffer_finish()

In the Linux kernel, the following vulnerability has been resolved: media: cx23885: Fix a null-ptr-deref bug in bufferprepare and bufferfinish When the driver calls cx23885riscbuffer to prepare the buffer, the function call dmaalloccoherent may fail, resulting in a empty buffer risc-cpu. Later wh...