lib: Move lib/rp2040/elf2uf2 to lib/elf2uf2

Recent versions of the rp2040 sdk no longer contain the elf2uf2 tool.
So, move that code to a new dedicated directory.  This is in
preparation for updating the rp2040 sdk version.

Signed-off-by: Kevin O'Connor <[email protected]>

lib/README

@@ -111,6 +111,11 @@ version 1.2.0 (bfcbefafc5d2a210551a4d9d80b4303d4ae0adf7). It has been
 modified so that it can build outside of the pico sdk. See
 rp2040.patch for the modifications.
 
+The elf2uf2 directory contains code from the pico sdk:
+  https://github.com/raspberrypi/pico-sdk.git
+version 1.2.0 (bfcbefafc5d2a210551a4d9d80b4303d4ae0adf7). Contents
+taken from the tools/elf2uf2/ directory.
+
 The rp2040_flash directory contains a light-weight bootsel flash tool.
 It uses C part of the the `picoboot_connection` directory found in:
   https://github.com/raspberrypi/picotool.git

src/rp2040/Makefile

@@ -3,7 +3,7 @@
 # Setup the toolchain
 CROSS_PREFIX=arm-none-eabi-
 
-dirs-y += src/rp2040 src/generic lib/rp2040/elf2uf2 lib/fast-hash lib/can2040
+dirs-y += src/rp2040 src/generic lib/elf2uf2 lib/fast-hash lib/can2040
 
 CFLAGS += -mcpu=cortex-m0plus -mthumb -Ilib/cmsis-core
 CFLAGS += -Ilib/rp2040 -Ilib/rp2040/cmsis_include -Ilib/fast-hash -Ilib/can2040
@@ -37,13 +37,13 @@ $(OUT)stage2.o: lib/rp2040/boot_stage2/$(STAGE2_FILE) $(OUT)autoconf.h
 	$(Q)$(CC) $(CFLAGS) -c $(OUT)stage2.S -o $(OUT)stage2.o
 
 # Binary output file rules when using stage2
-$(OUT)lib/rp2040/elf2uf2/elf2uf2: lib/rp2040/elf2uf2/main.cpp
+$(OUT)lib/elf2uf2/elf2uf2: lib/elf2uf2/main.cpp
 	@echo "  Building $@"
 	$(Q)g++ -g -O -Ilib/rp2040 $< -o $@
 
-$(OUT)klipper.uf2: $(OUT)klipper.elf $(OUT)lib/rp2040/elf2uf2/elf2uf2
+$(OUT)klipper.uf2: $(OUT)klipper.elf $(OUT)lib/elf2uf2/elf2uf2
 	@echo "  Creating uf2 file $@"
-	$(Q)$(OUT)lib/rp2040/elf2uf2/elf2uf2 $< $@
+	$(Q)$(OUT)lib/elf2uf2/elf2uf2 $< $@
 
 rptarget-$(CONFIG_RP2040_HAVE_STAGE2) := $(OUT)klipper.uf2
 stage2-$(CONFIG_RP2040_HAVE_STAGE2) := $(OUT)stage2.o