gallium: Don't emit identical endian-dependent pack/unpack code.

Reduces the size of the u_format_table.c file by 140k (out of 1.64M)
and makes me less confused about endianness in gallium.

Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Acked-by: Adam Jackson <ajax@redhat.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
22 jobs for !1697 with gallium-formats in 31 minutes and 15 seconds (queued for 17 minutes and 51 seconds)
detached
Status Name Job ID Coverage
  Containers Build
passed debian #546144

00:00:23

 
  Build+Test
passed meson-arm64 #546153

00:01:58

passed meson-armhf #546152

00:03:31

passed meson-clang #546146

00:04:48

passed meson-clover #546150

00:09:12

passed meson-i386 #546154

00:03:53

passed meson-main #546149

00:10:33

passed meson-swr-glvnd #546145

00:06:13

passed meson-vulkan #546151

00:02:56

passed scons-llvm #546156

00:03:52

passed scons-nollvm #546155

00:03:09

passed scons-swr #546147

00:05:38

passed scons-win64 #546148

00:06:48

 
  Test
passed test-llvmpipe-gles2 1/4 #546157

00:04:01

passed test-llvmpipe-gles2 2/4 #546158

00:04:10

passed test-llvmpipe-gles2 3/4 #546159

00:04:10

passed test-llvmpipe-gles2 4/4 #546160

00:04:39

passed test-softpipe-gles2 1/4 #546161

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passed test-softpipe-gles2 2/4 #546162

00:01:44

passed test-softpipe-gles2 3/4 #546163

00:01:39

passed test-softpipe-gles2 4/4 #546164

00:01:58

passed test-softpipe-gles3-limited #546165

00:04:14