CVE-2024-27028

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

spi: spi-mt65xx: Fix NULL pointer access in interrupt handler

The TX buffer in spi_transfer can be a NULL pointer, so the interrupt
handler may end up writing to the invalid memory and cause crashes.

Add a check to trans->tx_buf before using it.

More information : https://git.kernel.org/stable/c/1784053cf10a14c4ebd8a890bad5cfe1bee51713