Switch to using TARGET_TFM_LATEST

Rather than maintaining a specific `TARGET_TFM_V1_x`, its better to use
more generic name `TARGET_TFM_LATEST` to avoid confusion on the latest
TFM version supported by Mbed OS

* Rename the folder from `TARGET_TFM_V1_1` to `TARGET_TFM_LATEST`
* Update the CmakeLists.txt
* Change the name of the MUSCA targets to maintain uniformity
with TF-M v1.2
* Update target.json for PSA_V8_M to use `TFM_LATEST`

Author: jainvikas8

.gitignore

@@ -99,7 +99,8 @@ test_suite.json
 DELIVERY/
 
 # Directory used to clone and build TF-M
-features/FEATURE_EXPERIMENTAL_API/FEATURE_PSA/TARGET_TFM/TARGET_IGNORE/
+platform/FEATURE_EXPERIMENTAL_API/FEATURE_PSA/TARGET_TFM/TARGET_TFM_V1_0/TARGET_IGNORE/
+platform/FEATURE_EXPERIMENTAL_API/FEATURE_PSA/TARGET_TFM/TARGET_TFM_LATEST/TARGET_IGNORE/
 
 # CMake
 CMakeCache.txt

platform/FEATURE_EXPERIMENTAL_API/FEATURE_PSA/TARGET_TFM/CMakeLists.txt

@@ -5,6 +5,6 @@ if("TFM_V1_0" IN_LIST MBED_TARGET_LABELS)
     add_subdirectory(TARGET_TFM_V1_0)
 endif()
 
-if("TFM_V1_1" IN_LIST MBED_TARGET_LABELS)
-    add_subdirectory(TARGET_TFM_V1_1)
+if("TFM_LATEST" IN_LIST MBED_TARGET_LABELS)
+    add_subdirectory(TARGET_TFM_LATEST)
 endif()