Improve #endif comments

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/library/aes.c b/library/aes.c
index b750e7e..a64b2a5 100644
--- a/library/aes.c
+++ b/library/aes.c
@@ -95,8 +95,8 @@
     0x8C, 0xA1, 0x89, 0x0D, 0xBF, 0xE6, 0x42, 0x68,
     0x41, 0x99, 0x2D, 0x0F, 0xB0, 0x54, 0xBB, 0x16
 };
-#endif \
-    /* !defined(MBEDTLS_AES_ENCRYPT_ALT) || !defined(MBEDTLS_AES_SETKEY_ENC_ALT) || !defined(MBEDTLS_AES_SETKEY_DEC_ALT) */
+#endif /* !defined(MBEDTLS_AES_ENCRYPT_ALT) || !defined(MBEDTLS_AES_SETKEY_ENC_ALT) || \
+          !defined(MBEDTLS_AES_SETKEY_DEC_ALT) */
 
 /*
  * Forward tables
@@ -350,8 +350,8 @@
 #if !defined(MBEDTLS_AES_ENCRYPT_ALT) || !defined(MBEDTLS_AES_SETKEY_ENC_ALT) || \
     !defined(MBEDTLS_AES_SETKEY_DEC_ALT)
 static unsigned char FSb[256];
-#endif \
-    /* !defined(MBEDTLS_AES_ENCRYPT_ALT) || !defined(MBEDTLS_AES_SETKEY_ENC_ALT) || !defined(MBEDTLS_AES_SETKEY_DEC_ALT) */
+#endif /* !defined(MBEDTLS_AES_ENCRYPT_ALT) || !defined(MBEDTLS_AES_SETKEY_ENC_ALT) || \
+          !defined(MBEDTLS_AES_SETKEY_DEC_ALT) */
 #if !defined(MBEDTLS_AES_ENCRYPT_ALT) || !defined(MBEDTLS_AES_SETKEY_ENC_ALT)
 static uint32_t FT0[256];
 #if !defined(MBEDTLS_AES_FEWER_TABLES)
@@ -366,7 +366,7 @@
  */
 #if !(defined(MBEDTLS_AES_SETKEY_ENC_ALT) && defined(MBEDTLS_AES_DECRYPT_ALT))
 static unsigned char RSb[256];
-#endif
+#endif /* !(defined(MBEDTLS_AES_SETKEY_ENC_ALT) && defined(MBEDTLS_AES_DECRYPT_ALT)) */
 
 #if !defined(MBEDTLS_AES_DECRYPT_ALT) || !defined(MBEDTLS_AES_SETKEY_DEC_ALT)
 static uint32_t RT0[256];
@@ -591,8 +591,8 @@
 
     return 0;
 }
-#endif \
-    /* defined(MAY_NEED_TO_ALIGN) || !defined(MBEDTLS_AES_SETKEY_DEC_ALT) || !defined(MBEDTLS_AES_SETKEY_ENC_ALT) */
+#endif /* defined(MAY_NEED_TO_ALIGN) || !defined(MBEDTLS_AES_SETKEY_DEC_ALT) || \
+          !defined(MBEDTLS_AES_SETKEY_ENC_ALT) */
 
 /*
  * AES key schedule (encryption)