[app][hwcrypto] Improve C standards compliance

__offsetof => offsetof and include stddef.h

Include lk/compiler.h for countof.

Bug: 110158907
Change-Id: I16af82024ae7ac8e3f575c8db28988c5222ea536
diff --git a/app/hwcrypto/caam.c b/app/hwcrypto/caam.c
index eb11560..3b1920e 100644
--- a/app/hwcrypto/caam.c
+++ b/app/hwcrypto/caam.c
@@ -27,10 +27,12 @@
  */
 
 #include <assert.h>
+#include <lk/compiler.h>
 #include <lk/reg.h>
 #include <malloc.h>
 #include <openssl/digest.h>
 #include <openssl/hkdf.h>
+#include <stddef.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -101,9 +103,9 @@
         abort();
     }
 
-    writel((uint32_t)pmem.paddr + __offsetof(struct caam_job_rings, in),
+    writel((uint32_t)pmem.paddr + offsetof(struct caam_job_rings, in),
            CAAM_IRBAR0);  // input ring address
-    writel((uint32_t)pmem.paddr + __offsetof(struct caam_job_rings, out),
+    writel((uint32_t)pmem.paddr + offsetof(struct caam_job_rings, out),
            CAAM_ORBAR0);  // output ring address
 
     /* Initialize job ring sizes */