gallium/util: revert util_format_init addition

Putting calls to util_format_init all over the codebase is infeasible.

Instead, half float tables are pregenerated, and the s3tc library is
loaded on demand.

I believe this is a solution that combines performance, cleanliness,
flexibility and portability.

progs/gallium/unit/u_format_test.c

@@ -30,10 +30,8 @@
 #include <stdio.h>
 #include <float.h>
 
-#include "util/u_half.h"
 #include "util/u_format.h"
 #include "util/u_format_tests.h"
-#include "util/u_format_s3tc.h"
 
 
 static boolean
@@ -402,8 +400,6 @@ int main(int argc, char **argv)
 {
    boolean success;
 
-   util_format_init();
-
    success = test_all();
 
    return success ? 0 : 1;

src/gallium/auxiliary/util/u_format.c

@@ -117,11 +117,3 @@ util_format_write_4ub(enum pipe_format format, const uint8_t *src, unsigned src_
 
    format_desc->pack_8unorm(dst_row, dst_stride, src_row, src_stride, w, h);
 }
-
-boolean util_format_inited;
-
-void
-util_format_do_init(void)
-{
-   util_format_s3tc_init();
-}

src/gallium/auxiliary/util/u_format.h

@@ -552,8 +552,6 @@ util_format_write_4ub(enum pipe_format format,
                       void *dst, unsigned dst_stride, 
                       unsigned x, unsigned y, unsigned w, unsigned h);
 
-UTIL_INLINE_INIT(util_format);
-
 #ifdef __cplusplus
 } // extern "C" {
 #endif

src/gallium/drivers/nv50/nv50_context.c

@@ -71,8 +71,6 @@ nv50_create(struct pipe_screen *pscreen, void *priv)
 	struct nv50_screen *screen = nv50_screen(pscreen);
 	struct nv50_context *nv50;
 
-	util_format_init();
-
 	nv50 = CALLOC_STRUCT(nv50_context);
 	if (!nv50)
 		return NULL;

src/gallium/drivers/softpipe/sp_screen.c

@@ -224,7 +224,7 @@ softpipe_create_screen(struct sw_winsys *winsys)
    screen->base.context_create = softpipe_create_context;
    screen->base.flush_frontbuffer = softpipe_flush_frontbuffer;
 
-   util_format_init();
+   util_format_s3tc_init();
 
    softpipe_init_screen_texture_funcs(&screen->base);
    softpipe_init_screen_buffer_funcs(&screen->base);