Resolve semantic issue warning
Resolve semantic issue warning

This should resolve the semantic issue warning i get for that line:
```
BVLinearGradient.m:22:24: Incompatible pointer types sending 'CGColorRef' (aka 'struct CGColor *') to parameter of type 'id'
```
react-native-community/react-native-linear-gradient,react-native-community/react-native-linear-gradient,react-native-community/react-native-linear-gradient,react-native-community/react-native-linear-gradient