submodules: delete CMSIS_5 from the repository

See raspberrypi/pico-setup#57 Clones of debugprobe or invocations of pico-setup.sh frequently encounter errors relating to bandwidth budgets. These sporadic errors are due to the large size of the CMSIS_5 repo clone exhausting the bandwidth quotas on Github, so drop this in favour of a downstream copy of the relevant CMSIS-DAP firmware files. Users are advised to delete and regenerate the build directory. Optionally, reclaim filesystem space by removing .git/modules/CMSIS_5 and all subdirectories.

Author: P33M

.gitmodules

@@ -1,6 +1,3 @@
-[submodule "CMSIS_5"]
-path = CMSIS_5
-url = https://github.com/ARM-software/CMSIS_5
 [submodule "freertos"]
 path = freertos
 url = https://github.com/FreeRTOS/FreeRTOS-Kernel