i.pca: Fix Resource Leak issue

[ShubhamDesai]

This pull request fixes issue identified by coverity scan (CID : 1207830, 1207835, 1207833, 1207834, 1207836, 1207837)
G_free() is used.

[nilason]

If I'm not misreading the code, sum2 and rowbuf are both 2D arrays, of which each part also needs to be freed.

This will lead to too much repetitive code for freeing resources, so I'd suggest we use goto with a return value variable.

[ShubhamDesai]

If I'm not misreading the code, sum2 and rowbuf are both 2D arrays, of which each part also needs to be freed.

This will lead to too much repetitive code for freeing resources, so I'd suggest we use goto with a return value variable.

Done