arm/rtl22xx_t build failures

[Chris Johns]

On 24/05/2017 15:30, Sebastian Huber wrote:
>>
>> ../../../../../.././lpc1768_mbed/lib/include/bsp/lpc-i2s.h:26:25: 
>> fatal error: bsp/utility.h: No such file or directory
>>   #include <bsp/utility.h>
>>                           ^
>> compilation terminated.
> 
> Maybe its time to get rid of the make preinstall.
> 

I have not seen this again using the parallel build patch I just pushed. 
This change lets make correctly handle the dependencies between all the 
various phases and parts. This means preinstall is finished before any 
directories are entered to be built.

I am repeatably building all BSPs with and out tests. With the latest 
rtems-bsp-builder and `--jobs=7/8` I am seeing an average BSP build time 
around 47 seconds on a 16 core machine.

Chris