usbredir: Fix 32-bit build

Avoid these warnings from being errors:

usbredirhost.c: In function 'usbredirhost_can_write_iso_package':
usbredirhost.c:1023:19: warning: format '%lu' expects argument of type 'long unsigned int', but argument 4 has type 'uint64_t {aka long long unsigned int}' [-Wformat=]
             DEBUG("START dropping isoc packets %lu buffer > %lu hi threshold",
                   ^
usbredirhost.c:1023:19: warning: format '%lu' expects argument of type 'long unsigned int', but argument 5 has type 'uint64_t {aka long long unsigned int}' [-Wformat=]
             DEBUG("START dropping isoc packets %lu buffer > %lu hi threshold",
                   ^
usbredirhost.c:1028:19: warning: format '%lu' expects argument of type 'long unsigned int', but argument 4 has type 'uint64_t {aka long long unsigned int}' [-Wformat=]
             DEBUG("STOP dropping isoc packets %lu buffer < %lu low threshold",
                   ^
usbredirhost.c:1028:19: warning: format '%lu' expects argument of type 'long unsigned int', but argument 5 has type 'uint64_t {aka long long unsigned int}' [-Wformat=]
             DEBUG("STOP dropping isoc packets %lu buffer < %lu low threshold",
                   ^
usbredirhost.c: In function 'usbredirhost_set_iso_threshold':
usbredirhost.c:1162:11: warning: format '%lu' expects argument of type 'long unsigned int', but argument 4 has type 'uint64_t {aka long long unsigned int}' [-Wformat=]
     DEBUG("higher threshold is %lu bytes | lower threshold is %lu bytes",
           ^
usbredirhost.c:1162:11: warning: format '%lu' expects argument of type 'long unsigned int', but argument 5 has type 'uint64_t {aka long long unsigned int}' [-Wformat=]
     DEBUG("higher threshold is %lu bytes | lower threshold is %lu bytes",

I think in all of these cases, the incorrect format modifier just causes
wrong debug prints on i686.