pm: cpupower: rename raw_pylibcpupower.i

The raw_pylibcpupower.i is removed unexpectedly after 'make mrproper'

We can reproduce the error by performing the following steps:
cd linux-next
make mrproper
cd tools/power/cpupower/bindings/python
make

We will get an error message:
make: *** No rule to make target 'raw_pylibcpupower.i', needed by 'raw_pylibcpupower_wrap.c'. Stop.

The root cause:

The *.i files are already used for pre-processor output files and
the kernel removes all the *.i files by 'make mrproper'.

That explains why the raw_pylibcpupower.i is removed by 'make mrproper'.

To fix it, Follow John's suggestion to rename raw_pylibcpupower.i to
raw_pylibcpupower.swg.

See:
https://www.swig.org/Doc4.2/SWIG.html

Reviewed-by: John B. Wyatt IV <[e-mail]>
Reviewed-by: John B. Wyatt IV <[e-mail]>
Tested-by: John B. Wyatt IV <[e-mail]>
Tested-by: John B. Wyatt IV <[e-mail]>
Signed-off-by: Min-Hua Chen <[e-mail]>
Signed-off-by: Shuah Khan <[e-mail]>

tools/power/cpupower/bindings/python/Makefile

···
 raw_pylibcpupower_wrap.o: raw_pylibcpupower_wrap.c
 	$(CC) -fPIC -c raw_pylibcpupower_wrap.c $(PY_INCLUDE)
 
-raw_pylibcpupower_wrap.c: raw_pylibcpupower.i
+raw_pylibcpupower_wrap.c: raw_pylibcpupower.swg
 ifeq ($(HAVE_SWIG),0)
 	$(error "swig was not found. Make sure you have it installed and in the PATH to generate the bindings.")
 else ifeq ($(HAVE_PYCONFIG),0)
 	$(error "python-config was not found. Make sure you have it installed and in the PATH to generate the bindings.")
 endif
-	swig -python raw_pylibcpupower.i
+	swig -python raw_pylibcpupower.swg
 
 # Will only clean the bindings folder; will not clean the actual cpupower folder
 clean: