cnss2: Add module parameter for MHI timeout

Add a module parameter for MHI timeout which is only enabled in debug
builds to overwrite the default one from device tree. Also set it to
longer time for emulation setup.

Change-Id: I8d02c16d02f1e2e62027fd32545229717699f3ca
Signed-off-by: Yue Ma <yuem@codeaurora.org>