Use SEEK_* in lseek(2) calls

Change scripted with coccinelle:

@rule0@
expression A,B;
@@
- lseek(A, B, 0);
+ lseek(A, B, SEEK_SET);
@rule1@
expression A,B;
@@
- lseek(A, B, 1);
+ lseek(A, B, SEEK_CUR);
@rule2@
expression A,B;
@@
- lseek(A, B, 2);
+ lseek(A, B, SEEK_END);