Fix typo in gcm.h function comment

This commit fixes a type in a comment inside gcm.h.

Signed-off-by: Harry Ramsey <harry.ramsey@arm.com>
diff --git a/tf-psa-crypto/drivers/builtin/include/mbedtls/gcm.h b/tf-psa-crypto/drivers/builtin/include/mbedtls/gcm.h
index 741c814..692a0f9 100644
--- a/tf-psa-crypto/drivers/builtin/include/mbedtls/gcm.h
+++ b/tf-psa-crypto/drivers/builtin/include/mbedtls/gcm.h
@@ -175,7 +175,7 @@
  * \note            The output buffer \p output can be the same as the input
  *                  buffer \p input. If \p output is greater than \p input, they
  *                  cannot overlap. Implementations which require
- *                  MBEDTLS_GCM_ALT to be enabled may not provide support
+ *                  MBEDTLS_GCM_ALT to be enabled may not provide support for
  *                  overlapping buffers.
  *
  * \param ctx       The GCM context. This must be initialized.
@@ -285,7 +285,7 @@
  * \note            The output buffer \p output can be the same as the input
  *                  buffer \p input. If \p output is greater than \p input, they
  *                  cannot overlap. Implementations which require
- *                  MBEDTLS_GCM_ALT to be enabled may not provide support
+ *                  MBEDTLS_GCM_ALT to be enabled may not provide support for
  *                  overlapping buffers.
  *
  * \param ctx           The GCM context. This must be initialized.