staging: media: ipu7: fix double-free and use-after-free in error paths

Summary

In the Linux kernel, the following vulnerability has been resolved: staging: media: ipu7: fix double-free and use-after-free in error paths In both ipu7_isys_init() and ipu7_psys_init(), pdata is allocated and then passed to ipu7_bus_initialize_device(), which stores it in adev->pdata. The ipu7_bus_release() function frees adev->pdata when the device's reference count drops to zero. Two error paths incorrectly call kfree(pdata) after the device teardown has already freed it: 1. When ipu7_mmu_init() fails: put_device() is called, which drops the reference count to zero and triggers ipu7_bus_release() -> kfree(pdata). The subsequent kfree(pdata) is a double-free. 2. When ipu7_bus_add_device() fails: it calls auxiliary_device_uninit() internally, which calls put_device() -> ipu7_bus_release() -> kfree(pdata). The subsequent kfree(pdata) is again a double-free. Note that the kfree(pdata) when ipu7_bus_initialize_device() itself fails is correct, because in that case auxiliary_device_init() failed and the release function was never set up, so pdata must be freed manually. Additionally, the error code was not saved before calling put_device(), causing ERR_CAST() to dereference the already-freed adev pointer when constructing the return value. Fix this by saving the error from dev_err_probe() before put_device() and returning ERR_PTR() instead. Remove the redundant kfree(pdata) calls and fix the use-after-free in the return values of the two affected error paths.