Halt to enforce reboot limit once only

The pre-main check of error_reboot_count was applied repeatedly on
every boot, meaning that once the reboot limit was hit, every subsequent
reset would halt before main, until something managed to clear
or corrupt the error context.

Set the is_error_processed flag before halting, so that when an external
agent resets us while we're halted, we do not report the error and halt
again.

Author: kjbracey

platform/mbed_error.c

@@ -218,15 +218,16 @@ mbed_error_status_t mbed_error_initialize(void)
             //We let the callback reset the error info, so check if its still valid and do the rest only if its still valid.
             if (report_error_ctx->error_reboot_count > 0) {
 
+                report_error_ctx->is_error_processed = 1;//Set the flag that we already processed this error
+                crc_val = compute_crc32(report_error_ctx, offsetof(mbed_error_ctx, crc_error_ctx));
+                report_error_ctx->crc_error_ctx = crc_val;
+
                 //Enforce max-reboot only if auto reboot is enabled
 #if MBED_CONF_PLATFORM_FATAL_ERROR_AUTO_REBOOT_ENABLED
                 if (report_error_ctx->error_reboot_count >= MBED_CONF_PLATFORM_ERROR_REBOOT_MAX) {
                     mbed_halt_system();
                 }
 #endif
-                report_error_ctx->is_error_processed = 1;//Set the flag that we already processed this error
-                crc_val = compute_crc32(report_error_ctx, offsetof(mbed_error_ctx, crc_error_ctx));
-                report_error_ctx->crc_error_ctx = crc_val;
             }
         }
     }