env: Rework ENV_IS_EMBEDDED and related logic slightly

- Drop CONFIG_BUILD_ENVCRC as this is never set directly but instead
  means ENV_IS_EMBEDDED, so reference that in code and rename the Makefile
  usage to BUILD_ENVCRC.
- Remove extra-$(CONFIG_ENV_IS_EMBEDDED) line as it could never be true,
  and likely why there is an extra- line for CONFIG_ENV_IS_IN_FLASH (the
  only use case today of embedded environments).
- With these slight changes we can then see that using the calculated
  symbol of ENV_IS_EMBEDDED is the right thing to use in any code which
  needs to know this situation and can remove CONFIG_ENV_IS_EMBEDDED
  entirely.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/include/env_internal.h b/include/env_internal.h
index f30fd61..aee6b3e 100644
--- a/include/env_internal.h
+++ b/include/env_internal.h
@@ -41,10 +41,6 @@
 	(CONFIG_SYS_MONITOR_BASE + CONFIG_SYS_MONITOR_LEN)
 #  define ENV_IS_EMBEDDED
 # endif
-# ifdef CONFIG_ENV_IS_EMBEDDED
-#  error "do not define CONFIG_ENV_IS_EMBEDDED in your board config"
-#  error "it is calculated automatically for you"
-# endif
 #endif	/* CONFIG_ENV_IS_IN_FLASH */
 
 #if defined(CONFIG_ENV_IS_IN_NAND)
@@ -57,23 +53,6 @@
 # endif /* CONFIG_ENV_OFFSET_OOB */
 #endif /* CONFIG_ENV_IS_IN_NAND */
 
-/*
- * For the flash types where embedded env is supported, but it cannot be
- * calculated automatically (i.e. NAND), take the board opt-in.
- */
-#if defined(CONFIG_ENV_IS_EMBEDDED) && !defined(ENV_IS_EMBEDDED)
-# define ENV_IS_EMBEDDED
-#endif
-
-/* The build system likes to know if the env is embedded */
-#ifdef DO_DEPS_ONLY
-# ifdef ENV_IS_EMBEDDED
-#  ifndef CONFIG_ENV_IS_EMBEDDED
-#   define CONFIG_ENV_IS_EMBEDDED
-#  endif
-# endif
-#endif
-
 #include "compiler.h"
 
 #ifdef CONFIG_SYS_REDUNDAND_ENVIRONMENT
@@ -88,7 +67,7 @@
  * If the environment is in RAM, allocate extra space for it in the malloc
  * region.
  */
-#if defined(CONFIG_ENV_IS_EMBEDDED)
+#if defined(ENV_IS_EMBEDDED)
 #define TOTAL_MALLOC_LEN	CONFIG_SYS_MALLOC_LEN
 #elif (CONFIG_ENV_ADDR + CONFIG_ENV_SIZE < CONFIG_SYS_MONITOR_BASE) || \
       (CONFIG_ENV_ADDR >= CONFIG_SYS_MONITOR_BASE + CONFIG_SYS_MONITOR_LEN) || \