hidpp20-drv: prevent an empty profile to try to read a null macro
hidpp20-drv: prevent an empty profile to try to read a null macro

If the macro has not been retrieved, it's more likely that the button
is not bound to anything.

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

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