ext2simg: fix error check of io_channel_read_blk64()

Check the return value of io_channel_read_blk64() correctly, considering
that it returns an errcode_t, which can be positive.

Fixes: db6f320912cf ("AOSP: android: add the ext2simg tool")
Change-Id: Iafc6c0169bc8ac79198f285da0246ff3b841ded8
Signed-off-by: Eric Biggers <ebiggers@google.com>
1 file changed