* arm-tdep.c (arm_use_struct_convention): Make static. Move to be

* arm-tdep.c (arm_use_struct_convention): Make static.  Move to be
with other related struct-returning functions.
(arm_extract_struct_value_address): New function.
(arm_gdbarch_init): Initialize the above in multi-arch vector.  Also
initialize float_format, double_format and long_double_format as
appropriate to the endianness of the target.
* config/arm/tm-arm.h (TARGET_DOUBLE_FORMAT): Delete.
(arm_use_struct_convention): Delete declaration.
(USE_STRUCT_CONVENTION, EXTRACT_STRUCT_VALUE_ADDRESS): Delete.