staging: kpc2000: kpc_i2c: use %s with __func__ identifier in log messages

Throughout i2c_driver.c, there are instances where the log strings
contain the function's name hardcoded into the string. Instead, use the
printk conversion specifier '%s' with the __func__ preprocessor
identifier to more maintainably print the function's name.

Signed-off-by: Geordan Neukum <gneukum1@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>