Deprecate hardware acceleration errors

Deprecate the module-specific XXX_HW_ACCEL_FAILED and
XXX_FEATURE_UNAVAILABLE errors, as alternative implementations should now
return `MBEDTLS_ERR_PLATFORM_HW_FAILED` and
`MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED`.

library/aes.c

diff --git a/library/aes.c b/library/aes.c
index 5c939bb..eab9043 100644
--- a/library/aes.c
+++ b/library/aes.c
@@ -36,6 +36,7 @@
 #include <string.h>
 
 #include "mbedtls/aes.h"
+#include "mbedtls/platform.h"
 #include "mbedtls/platform_util.h"
 #if defined(MBEDTLS_PADLOCK_C)
 #include "mbedtls/padlock.h"
@@ -1757,7 +1758,7 @@
          * there is an alternative underlying implementation i.e. when
          * MBEDTLS_AES_ALT is defined.
          */
-        if( ret == MBEDTLS_ERR_AES_FEATURE_UNAVAILABLE && keybits == 192 )
+        if( ret == MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED && keybits == 192 )
         {
             mbedtls_printf( "skipped\n" );
             continue;
@@ -1821,7 +1822,7 @@
          * there is an alternative underlying implementation i.e. when
          * MBEDTLS_AES_ALT is defined.
          */
-        if( ret == MBEDTLS_ERR_AES_FEATURE_UNAVAILABLE && keybits == 192 )
+        if( ret == MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED && keybits == 192 )
         {
             mbedtls_printf( "skipped\n" );
             continue;
@@ -1886,7 +1887,7 @@
          * there is an alternative underlying implementation i.e. when
          * MBEDTLS_AES_ALT is defined.
          */
-        if( ret == MBEDTLS_ERR_AES_FEATURE_UNAVAILABLE && keybits == 192 )
+        if( ret == MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED && keybits == 192 )
         {
             mbedtls_printf( "skipped\n" );
             continue;
@@ -1949,7 +1950,7 @@
          * there is an alternative underlying implementation i.e. when
          * MBEDTLS_AES_ALT is defined.
          */
-        if( ret == MBEDTLS_ERR_AES_FEATURE_UNAVAILABLE && keybits == 192 )
+        if( ret == MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED && keybits == 192 )
         {
             mbedtls_printf( "skipped\n" );
             continue;