saa_fread/fwrite: when seeking, must set [rw]ptr as well
saa_fread/fwrite: when seeking, must set [rw]ptr as well

[rw]ptr represent the global position and need to be kept in sync with
[rw]pos:[rw]blk at all times.  Failed to do that while seeking, with
obviously bad results.

techkey/nasm,techkey/nasm,letolabs/nasm,turingstudio/nasm,Distrotech/nasm,letolabs/nasm,projedi/nasm,turingstudio/nasm,Distrotech/nasm,techkey/nasm,letolabs/nasm,projedi/nasm,Distrotech/nasm,techkey/nasm,techkey/nasm,projedi/nasm,turingstudio/nasm,projedi/nasm,Distrotech/nasm,projedi/nasm,turingstudio/nasm