Adjust layout of some stucts

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index 2b9eca8..0a5ecc8 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -104,9 +104,9 @@
 #define RNG_SEEDED 2
 
 typedef struct {
-    unsigned initialized : 1;
-    unsigned rng_state : 2;
-    unsigned drivers_initialized : 1;
+    uint8_t initialized;
+    uint8_t rng_state;
+    uint8_t drivers_initialized;
     mbedtls_psa_random_context_t rng;
 } psa_global_data_t;