u-boot: Fix several typos

's/environemnt/environment/' and
	's/Environemnt/Environment/'

Signed-off-by: Shyam Saini <shyam@amarulasolutions.com>
diff --git a/include/environment.h b/include/environment.h
index 50c62c5..70b7eda 100644
--- a/include/environment.h
+++ b/include/environment.h
@@ -292,7 +292,7 @@
 /**
  * env_get_char() - Get a character from the early environment
  *
- * This reads from the pre-relocation environemnt
+ * This reads from the pre-relocation environment
  *
  * @index: Index of character to read (0 = first)
  * @return character read, or -ve on error