staging: kpc2000: move the i2c driver out of its subdirectory

There is no need for a subdirectory for just a single .c file.  So move
it out of kpc_i2c/ and rename it to the module name that we want the
file to build to, saving one more linking stage.

Cc: Matt Sickler <Matt.Sickler@daktronics.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>