Reduced build sources to just the core littlefs

Currently this is just lfs.c and lfs_util.c. Previously this included
the block devices, but this meant all of the scripts needed to
explicitly deselect the block devices to avoid reporting build
size/coverage info on them.

Note that test.py still explicitly adds the block devices for compiling
tests, which is their main purpose. Humorously this means the block
devices will probably be compiled into most builds in this repo anyways.

.github/workflows/test.yml

@@ -138,14 +138,7 @@ jobs:
 #          make test TESTFLAGS+="-nrk \
 #            -DLFS_READ_SIZE=11 -DLFS_BLOCK_SIZE=704"
 
-      # collect coverage
-      - name: collect-coverage
-        continue-on-error: true
-        run: |
-          # we only care about littlefs's actual source
-          lcov -e coverage/${{github.job}}-${{matrix.arch}}.info \
-            $(for f in lfs*.c ; do echo "/$f" ; done) \
-            -o coverage/${{github.job}}-${{matrix.arch}}.info
+      # upload coveragefor later coverage
       - name: upload-coverage
         continue-on-error: true
         uses: actions/upload-artifact@v2
@@ -159,10 +152,8 @@ jobs:
         continue-on-error: true
         run: |
           mkdir -p results
-          # TODO remove the need for SRC
           make clean
           make code \
-            SRC="$(echo lfs*.c)" \
             CFLAGS+=" \
               -DLFS_NO_ASSERT \
               -DLFS_NO_DEBUG \
@@ -175,7 +166,6 @@ jobs:
           mkdir -p results
           make clean
           make code \
-            SRC="$(echo lfs*.c)" \
             CFLAGS+=" \
               -DLFS_NO_ASSERT \
               -DLFS_NO_DEBUG \
@@ -189,7 +179,6 @@ jobs:
           mkdir -p results
           make clean
           make code \
-            SRC="$(echo lfs*.c)" \
             CFLAGS+=" \
               -DLFS_NO_ASSERT \
               -DLFS_NO_DEBUG \
@@ -203,7 +192,6 @@ jobs:
           mkdir -p results
           make clean
           make code \
-            SRC="$(echo lfs*.c)" \
             CFLAGS+=" \
               -DLFS_NO_ASSERT \
               -DLFS_NO_DEBUG \