Build: Update the Musca-B1 path

The Musca-B1 platform port was moved from "arm/musca_b1/sse_200" to
"arm/musca_b1".
Remains of deprecated ports also removed, as:
- "arm/mps2/an539"
- "arm/mps2/sse-200_aws"
- "arm/musca_b1/secure_enclave"

Signed-off-by: Mark Horvath <mark.horvath@arm.com>
Change-Id: Ie674ef5c0cea9c7dfb104ccee3f6c3c8e0bcf50e
5 files changed