drm/nouveau/ram: fix test for gpio presence

#define ram_init(s,p)       ramfuc_init(&(s)->base, (p))

#define ram_exec(s,e)       ramfuc_exec(&(s)->base, (e))

#define ram_have(s,r)       ((s)->r_##r.addr != 0x000000)

#define ram_have(s,r)       ((s)->r_##r.addr[0] != 0x000000)

#define ram_rd32(s,r)       ramfuc_rd32(&(s)->base, &(s)->r_##r)

#define ram_wr32(s,r,d)     ramfuc_wr32(&(s)->base, &(s)->r_##r, (d))

#define ram_nuke(s,r)       ramfuc_nuke(&(s)->base, &(s)->r_##r)