arm: Define with_float to hard when target name ends with hf

arm: Define with_float to hard when target name ends with hf

On arm, the --with-float= configure option is used to define include
files search path (among other things).  However, when targeting
arm-linux-gnueabihf, one would expect to automatically default to the
hard-float ABI, but this is not the case. As a consequence, GCC
bootstrap fails on an arm-linux-gnueabihf target if --with-float=hard
is not used.

This patch checks if the target name ends with 'hf' and defines
with_float to hard if not already defined.  This is achieved in
gcc/config.gcc, just before selecting the default CPU depending on the
$with_float value.

2022-08-17  Christophe Lyon  <christophe.lyon@arm.com>

	gcc/
	* config.gcc (arm): Define with_float to hard if target name ends
	with 'hf'.