lm4f: Compile with FPU support

Specify the -mfloat-abi=hard and -mfpu=fpv4-sp-d16 flags so that FPU
is enabled by default.
While this compiles with FPU support, in order to use the floating point types,
the FPU must be explicitly enabled at runtime.

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>

examples/lm4f/Makefile.include

@@ -36,7 +36,7 @@ $(info We seem to be building the example in the source directory. Using local l
 endif
 endif
 
-ARCH_FLAGS      = -mthumb -mcpu=cortex-m4
+ARCH_FLAGS      = -mthumb -mcpu=cortex-m4 -mfloat-abi=hard -mfpu=fpv4-sp-d16
 CFLAGS		+= -O0 -g3 -Wall -Wextra -I$(TOOLCHAIN_DIR)/include \
 		   -fno-common $(ARCH_FLAGS) -MD -DLM4F
 LDSCRIPT	?= $(BINARY).ld

lib/lm4f/Makefile

@@ -24,7 +24,7 @@ PREFIX		?= arm-none-eabi
 CC		= $(PREFIX)-gcc
 AR		= $(PREFIX)-ar
 CFLAGS		= -Os -g -Wall -Wextra -I../../include -fno-common \
-		  -mcpu=cortex-m4 -mthumb -Wstrict-prototypes \
+		  -mcpu=cortex-m4 -mthumb -mfloat-abi=hard -Wstrict-prototypes \
 		  -ffunction-sections -fdata-sections -MD -DLM4F
 # ARFLAGS	= rcsv
 ARFLAGS		= rcs