fix build on 32-bit Windows

[drakkan]

I've included #1525 in SFTPGo. Manual tests are ok and SFTPGo test suite passes too, thanks for improving Windows support!
However CI fails with this error

C:\Users\runneradmin\go\pkg\mod\github.com\jackc\pgx\[email protected]\internal\nbconn\nbconn_real_non_block_windows.go:27:33: cannot use 0x8004667e (untyped int constant 2147772030) as int value in constant declaration (overflows)

https://github.com/drakkan/sftpgo/actions/runs/4336134809/jobs/7571210333

CI builds SFTPGo for amd64, arm64 and 386. This patch fixes the 32-bit build

[jackc]

Thanks!