Fix spelling of 'reasonable' in comments

Signed-off-by: Tom Cosgrove <tom.cosgrove@arm.com>
diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index b0296eb..a1891bf 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -1493,7 +1493,7 @@
  * Enable an implementation of SHA-256 that has lower ROM footprint but also
  * lower performance.
  *
- * The default implementation is meant to be a reasonnable compromise between
+ * The default implementation is meant to be a reasonable compromise between
  * performance and size. This version optimizes more aggressively for size at
  * the expense of performance. Eg on Cortex-M4 it reduces the size of
  * mbedtls_sha256_process() from ~2KB to ~0.5KB for a performance hit of about
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 610b8b1..328f861 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -4357,7 +4357,7 @@
 void mbedtls_ssl_config_init( mbedtls_ssl_config *conf );
 
 /**
- * \brief          Load reasonnable default SSL configuration values.
+ * \brief          Load reasonable default SSL configuration values.
  *                 (You need to call mbedtls_ssl_config_init() first.)
  *
  * \param conf     SSL configuration context
diff --git a/include/mbedtls/ssl_ticket.h b/include/mbedtls/ssl_ticket.h
index a882eed..8221051 100644
--- a/include/mbedtls/ssl_ticket.h
+++ b/include/mbedtls/ssl_ticket.h
@@ -101,7 +101,7 @@
  *                  supported. Usually that means a 256-bit key.
  *
  * \note            The lifetime of the keys is twice the lifetime of tickets.
- *                  It is recommended to pick a reasonnable lifetime so as not
+ *                  It is recommended to pick a reasonable lifetime so as not
  *                  to negate the benefits of forward secrecy.
  *
  * \return          0 if successful,