[portaudio] Fix library cannot be found

[NancyLi1013]

Since the generated library name such as portaudio_x64.lib is renamed as portaudio.lib in portfile.cmake file. While in portaudioTargets.cmake, it keeps the original name portaudio_x64.lib .
So when using this port, it cannot be found by CMake.
I fix this issue by setting PA_LIBNAME_ADD_SUFFIX as OFF` and remove these codes in CMakeLists file:

IF(MSVC AND PA_BUILD_STATIC AND PA_BUILD_SHARED AND NOT PA_LIBNAME_ADD_SUFFIX)
  MESSAGE(WARNING "Building both shared and static libraries, and avoiding the suffix _static will lead to a name conflict")
  SET(PA_LIBNAME_ADD_SUFFIX ON CACHE BOOL "Forcing use of suffix _static to avoid name conflict between static and import library" FORCE)
  MESSAGE(WARNING "PA_LIBNAME_ADD_SUFFIX was set to ON")
ENDIF()

At the same time, remove the related operations that rename library name.

Related issue #8834, #8869.
Note: No features need to test.

[traversaro]

cc @GiulioRomualdi

[GiulioRomualdi]

Dear @NancyLi1013 thanks for fixing the problem. Now portaudio is found by the cmake project. However as I wrote in #8834 (comment), the compilation phase failed when #include<portaudio.h> is added to the project.

[NancyLi1013]

/azp run