cnss2: Ignore debugfs non availability during init

Debugfs is used for bringup support and debug. Ignore debugfs
setup failure if it is not supported in kernel config.

Change-Id: I07a56a0ce4adf53e0aa5b00ce73310d0c7ed2f6a
Signed-off-by: Manikandan Mohan <manikand@codeaurora.org>