Docs: Consistently refer to Musca-A

Updates documents to consistently refer to Musca-A, rather than using a
mix of Musca-A and Musca-A1.

Change-Id: I6f7a9e6afe3475b4a88200f6e56bf4c5507850e4
Signed-off-by: Jamie Fox <jamie.fox@arm.com>
diff --git a/docs/user_guides/tfm_build_instruction.rst b/docs/user_guides/tfm_build_instruction.rst
index 2b8c557..4097b71 100644
--- a/docs/user_guides/tfm_build_instruction.rst
+++ b/docs/user_guides/tfm_build_instruction.rst
@@ -29,7 +29,7 @@
             ``-DTARGET_PLATFORM=AN521``
           - Cortex-M23 IoT Kit subsystem for MPS2+ (AN519)
             ``-DTARGET_PLATFORM=AN519``
-          - Musca-A1 test chip board (Cortex-M33 SSE-200 subsystem)
+          - Musca-A test chip board (Cortex-M33 SSE-200 subsystem)
             ``-DTARGET_PLATFORM=MUSCA_A``
           - Musca-B1 test chip board (Cortex-M33 SSE-200 subsystem)
             ``-DTARGET_PLATFORM=MUSCA_B1``