CVE-2026-64234 tty: serial: pch_uart: add check for dma_alloc_coherent()

In the Linux kernel, the following vulnerability has been resolved: tty: serial: pchuart: add check for dmaalloccoherent Add a check for dmaalloccoherent failure to prevent a potential NULL pointer dereference in dmahandlerx. Properly release DMA channels and the PCI device reference using a goto...