plugins,tests: avoid cast-align errors

We can safely cast the data in a GArray to gpointer first, and then
to the pointer type we require.

  tests/test-helpers.c: In function 'mm_test_helpers_compare_bands':
  tests/test-helpers.c:41:47: error: cast increases required alignment of target type [-Werror=cast-align]
       bands_str = mm_common_build_bands_string ((MMModemBand *)(bands->data), bands->len);
                                                 ^
  tests/test-helpers.c:46:56: error: cast increases required alignment of target type [-Werror=cast-align]
       expected_bands_str = mm_common_build_bands_string ((MMModemBand *)(expected_bands_array->data), expected_bands_array->len);
                                                          ^

0 files changed, 0 insertions, 0 deletions