Data type correction in pgstat_report_replslot function parameters

Hi,

While I was reviewing replication slot statistics code, I found one
issue in the data type used for pgstat_report_replslot function
parameters. We pass int64 variables to the function but the function
prototype uses int type. I I felt the function parameters should be
int64. Attached patch fixes the same.
Thoughts?

Regards,
Vignesh