fix(tree): correct some typos

found using codespell (https://github.com/codespell-project/codespell).

Signed-off-by: Elyes Haouas <ehaouas@noos.fr>
Change-Id: I1bfa797e3460adddeefa916bb68e22beddaf6373
diff --git a/include/bl31/ehf.h b/include/bl31/ehf.h
index c13d28c..63943a9 100644
--- a/include/bl31/ehf.h
+++ b/include/bl31/ehf.h
@@ -30,7 +30,7 @@
 		.ehf_handler = EHF_NO_HANDLER_, \
 	}
 
-/* Macro for platforms to regiter its exception priorities */
+/* Macro for platforms to register its exception priorities */
 #define EHF_REGISTER_PRIORITIES(priorities, num, bits) \
 	const ehf_priorities_t exception_data = { \
 		.num_priorities = (num), \