Fix build of liquidio with base gcc on i386

[dim]

Summary

Base gcc fails to compile sys/dev/liquidio/lio_main.c for i386, with
the following -Werror warnings:

cc1: warnings being treated as errors
/usr/src/sys/modules/lio/../../dev/liquidio/lio_main.c: In function 'lio_setup_glists':
/usr/src/sys/modules/lio/../../dev/liquidio/lio_main.c:1774: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
/usr/src/sys/modules/lio/../../dev/liquidio/lio_main.c:1775: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]

This is because on i386, the casts from uint64_t to a pointer reduce
the values from 64 bit to 32 bit, and vice versa.

For gcc, this can be fixed by intermediate casts to uintptr_t. Note
that I am assuming the incoming values will always fit into 32 bit!

[sbruno]