Fix up typos

Ran automated checker for common typos [1]. Most of these changes have
no functional change *except* for `./ci/sim_run.sh` where, previously
the `bootstrap` feature wasn't being selected properly.

I didn't touch anything in the `./ext/` folder as anything in there
should probably be fixed in the upstream repo.

[1] https://github.com/codespell-project/codespell

Signed-off-by: Sam Bristow <sam@bristow.nz>
diff --git a/boot/bootutil/src/loader.c b/boot/bootutil/src/loader.c
index 3ee6335..5e12891 100644
--- a/boot/bootutil/src/loader.c
+++ b/boot/bootutil/src/loader.c
@@ -383,7 +383,7 @@
 }
 
 /*
- * Slots are compatible when all sectors that store upto to size of the image
+ * Slots are compatible when all sectors that store up to to size of the image
  * round up to sector size, in both slot's are able to fit in the scratch
  * area, and have sizes that are a multiple of each other (powers of two
  * presumably!).
@@ -915,7 +915,7 @@
  * Check that there is a valid image in a slot
  *
  * @returns
- *         0 if image was succesfully validated
+ *         0 if image was successfully validated
  *         1 if no bootloable image was found
  *         -1 on any errors
  */