hidpp20: prevent segfault if hidpp20_adjustable_dpi_get_dpi() fails
hidpp20: prevent segfault if hidpp20_adjustable_dpi_get_dpi() fails

Signed-off-by: Benjamin Tissoires <7a0e50e3f6a0939db82b6a8a423c08a163896f41@gmail.com>

whot/libratbag,whot/libratbag,cvuchener/libratbag,cvuchener/libratbag,libratbag/libratbag,whot/libratbag,cvuchener/libratbag,libratbag/libratbag,libratbag/libratbag