configure: Define TARGET_LONG_BITS in configs/targets/*.mak

configure: Define TARGET_LONG_BITS in configs/targets/*.mak

Define TARGET_LONG_BITS in each target's configure fragment.
Do this without removing the define in target/*/cpu-param.h
so that errors are caught like so:

In file included from .../src/include/exec/cpu-defs.h:26,
                 from ../src/target/hppa/cpu.h:24,
                 from ../src/linux-user/qemu.h:4,
                 from ../src/linux-user/hppa/cpu_loop.c:21:
../src/target/hppa/cpu-param.h:11: error: "TARGET_LONG_BITS" redefined [-Werror]
   11 | #define TARGET_LONG_BITS              64
      |
In file included from .../src/include/qemu/osdep.h:36,
                 from ../src/linux-user/hppa/cpu_loop.c:20:
./hppa-linux-user-config-target.h:32: note: this is the location of the previous definition
   32 | #define TARGET_LONG_BITS 32
      |
cc1: all warnings being treated as errors

Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>