Remove depreciated blackfin build

Blackfin toolchain is too old to build lwext4 correctly

Makefile

@@ -27,13 +27,7 @@ generic:
 	cd build_generic && cmake -G"Unix Makefiles"          \
 	$(COMMON_DEFINITIONS)                                 \
 	-DCMAKE_TOOLCHAIN_FILE=../toolchain/generic.cmake ..
-	
-bf518:
-	rm -R -f build_bf518
-	mkdir build_bf518
-	cd build_bf518 && cmake -G"Unix Makefiles"            \
-	$(COMMON_DEFINITIONS)                                 \
-	-DCMAKE_TOOLCHAIN_FILE=../toolchain/bf518.cmake ..
+
 
 avrxmega7:
 	rm -R -f build_avrxmega7

README.md

@@ -194,14 +194,6 @@ For other targets compilation passes (with warnings somewhere) but tests are
 not done yet. Lwext4 code is written with endianes respect. Big endian
 behavior also hasn't been tested yet.
 
-Build bf518 library:
-------------
-```bash
- make bf518
- cd build_bf518
- make lwext4
- ```
-
 Build avrxmega7 library:
 ------------
 ```bash

toolchain/bf518.cmake

@@ -1,7 +0,0 @@
-# Name of the target
-set(CMAKE_SYSTEM_NAME Generic)
-set(CMAKE_SYSTEM_PROCESSOR bf518)
-
-set(MCPU_FLAGS "-mcpu=bf518")
-
-include(${CMAKE_CURRENT_LIST_DIR}/common/bfin-elf.cmake)