[Patch,ld] Support cflags, ldflags from board description file in ld tests

[nick clifton]

Hi Vidya,
>> 2013-12-11  Vidya Praveen  <vidyapraveen@arm.com>
>>
>>          * lib/ld-lib.exp (default_ld_link): Use ldflags from board description
>>          file.
>>          (default_ld_simple_link): Likewise.
>>          (default_ld_compile): Use cflags from board description file.

Approved and applied.

Cheers
   Nick