CVE-2026-23464: soc: microchip: mpfs: Fix memory leak in mpfs_sys_controller_probe()

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

soc: microchip: mpfs: Fix memory leak in mpfssyscontrollerprobe()

In mpfssyscontrollerprobe(), if ofgetmtddevicebynode() fails, the function returns immediately without freeing the allocated memory for syscontroller, leading to a memory leak.

Fix this by jumping to the outfree label to ensure the memory is properly freed.

Also, consolidate the error handling for the mboxrequestchannel() failure case to use the same label.