secure_fw: Fix spelling typos

Signed-off-by: Antonio de Angelis <antonio.deangelis@arm.com>
Change-Id: I58da18eb39f746c169e7e401d921b84e13d70345
diff --git a/secure_fw/spm/include/bitops.h b/secure_fw/spm/include/bitops.h
index ed3ddd9..ce3aef4 100644
--- a/secure_fw/spm/include/bitops.h
+++ b/secure_fw/spm/include/bitops.h
@@ -9,7 +9,7 @@
 
 #include <stdint.h>
 
-/* Check if there is only one bit availiable in a 32bit number */
+/* Check if there is only one bit available in a 32bit number */
 #define IS_ONLY_ONE_BIT_IN_UINT32(n)                          \
                   ((uint32_t)(n) && !((uint32_t)(n) & ((uint32_t)(n)-1)))
 #endif /* __BITOPS_H__ */