u-boot: Fix several typos

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

Signed-off-by: Shyam Saini <shyam@amarulasolutions.com>
diff --git a/common/spl/Kconfig b/common/spl/Kconfig
index 431710a..1f14797 100644
--- a/common/spl/Kconfig
+++ b/common/spl/Kconfig
@@ -334,7 +334,7 @@
 	  example OS may set "reboot_image" environment variable to
 	  "recovery" inorder to boot recovery image by SPL. The SPL read
 	  "reboot_image" and act accordingly and change the reboot_image
-	  to default mode using setenv and save the environemnt.
+	  to default mode using setenv and save the environment.
 
 config SPL_ETH_SUPPORT
 	bool "Support Ethernet"