huion: Fail on parameter retrieval errors

Fail Huion tablet interface enabling and probing, if parameter retrieval
fails. Move the main code path out of the else block accordingly.

This should prevent devices appearing in a half-working state due to
original report descriptor being used, simplifying diagnostics. This
also makes it easier to add cleanup in later commits, as error handling
is simplified.
huion: Use allocated buffer for DMA

Allocate a buffer with kmalloc for receiving the parameters string
descriptor with usb_control_msg, instead of using a buffer on the stack,
as the latter is unsafe. Use an enum for indices into the buffer to
ensure the buffer size if sufficient.

This fixes the static checker error "doing dma on the stack (buf)".

Signed-off-by: Nikolai Kondrashov <spbnick@gmail.com>
Add .vimrc

Add .vimrc with settings catering to kernel coding standards.