[PATCH v3] erofs-utils: lib: fix infinite loop on EOF in erofs_io_xcopy

[Nithurshen]

Hi Ajay,

As a fellow contributor and reviewer, one small request.
Kindly send the next versions of patches (i.e. v2, v3, etc.) in the
same thread to keep the mailing list list clean and easy for 
reviewers to follow up.

Thanks and Regards,
Nithurshen