meson.build: Remove redundent csp_shlib and csp_shdep
meson.build: Remove redundent csp_shlib and csp_shdep

Meson allows you to specify either static or shared library at build
time with `default_library`.

From a parent project, you can either:

    meson setup builddir

or

    meson setup builddir -Ddefault_library=static

If you have newer Meson than libcsp requires, you can also specify it
in `dependency()`.

Thus, we don't need two distinct deps for each library.

ref)
https://mesonbuild.com/Release-notes-for-0-54-0.html#per-subproject-default_library-and-werror-options
https://mesonbuild.com/Release-notes-for-0-60-0.html#dependency-sets-default_library-on-fallback-subproject

Signed-off-by: Yasushi SHOJI <afa9ca3be149447780c2f7b524d61ed3d3db63f9@spacecubics.com>

libcsp/libcsp,libcsp/libcsp