We can safely cast the data in a GArray to gpointer first, and then
to the pointer type we require.
cinterion/mm-modem-helpers-cinterion.c: In function 'mm_cinterion_build_band':
cinterion/mm-modem-helpers-cinterion.c:409:54: error: cast increases required alignment of target type [-Werror=cast-align]
bands_string = mm_common_build_bands_string ((MMModemBand *)bands->data, bands->len);
^