For better understanding of relationship between headers and modules
rename:
	intel_bxtwc.h -> intel_soc_pmic_bxtwc.h

While here, remove file name from the file itself.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NLee Jones <lee.jones@linaro.org>