usb: gadget: f_ipc: Increase max packet size to 24k

The IPC packet size requirement has increased in order to
support maximum GNSS SV measurements. Increase the max packet
size to 24k for the same.

Change-Id: I9e4f6d73f132d271125862e42f0a4f369f65fc7f
Signed-off-by: Ajay Agarwal <ajaya@codeaurora.org>