cmd: booti: Fix spelling of "environment".

Signed-off-by: Vagrant Cascadian <vagrant@debian.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/cmd/booti.c b/cmd/booti.c
index ae37975..af0603b 100644
--- a/cmd/booti.c
+++ b/cmd/booti.c
@@ -141,7 +141,7 @@
 	"\tspecifying the size of a RAW initrd.\n"
 	"\tCurrently only booting from gz, bz2, lzma and lz4 compression\n"
 	"\ttypes are supported. In order to boot from any of these compressed\n"
-	"\timages, user have to set kernel_comp_addr_r and kernel_comp_size enviornment\n"
+	"\timages, user have to set kernel_comp_addr_r and kernel_comp_size environment\n"
 	"\tvariables beforehand.\n"
 #if defined(CONFIG_OF_LIBFDT)
 	"\tSince booting a Linux kernel requires a flat device-tree, a\n"