clean-up: Remove the no more necessary ENV_HAS_DATA_SECTION flag

With commit b7832de026 ("x86: Add .data
section support for pre-memory stages"), the `ENV_HAS_DATA_SECTION'
flag and its derivatives can now be removed from the code.

Change-Id: Ic0afac76264a9bd4a9c93ca35c90bd84e9b747a2
Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/77291
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Maximilian Brune <maximilian.brune@9elements.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/lib/cbfs.c

@@ -20,12 +20,8 @@
 #include <thread.h>
 #include <timestamp.h>
 
-#if ENV_HAS_DATA_SECTION
 struct mem_pool cbfs_cache =
 	MEM_POOL_INIT(_cbfs_cache, REGION_SIZE(cbfs_cache), CONFIG_CBFS_CACHE_ALIGN);
-#else
-struct mem_pool cbfs_cache = MEM_POOL_INIT(NULL, 0, 0);
-#endif
 
 static void switch_to_postram_cache(int unused)
 {