[Ada] Small adjustments to fixed-point I/O units

[Ada] Small adjustments to fixed-point I/O units

gcc/ada/

	* libgnat/a-tifiio.adb: Adjust documentation.
	(OK_Get_32): Compare the object size of the base type.
	(OK_Put_32): Likewise.
	(OK_Get_64): Likewise.
	(OK_Put_64): Likewise.
	* libgnat/a-tifiio__128.adb: Adjust documentation.
	(OK_Get_32): Compare the object size of the base type.
	(OK_Put_32): Likewise.
	(OK_Get_64): Likewise.
	(OK_Put_64): Likewise.
	(OK_Get_128): Likewise.
	(OK_Put_128): Likewise.
	* libgnat/a-wtfiio.adb (OK_Get_32): Likewise.
	(OK_Put_32): Likewise.
	(OK_Get_64): Likewise.
	(OK_Put_64): Likewise
	* libgnat/a-wtfiio__128.adb (OK_Get_32): Likewise.
	(OK_Put_32): Likewise.
	(OK_Get_64): Likewise.
	(OK_Put_64): Likewise.
	(OK_Get_128): Likewise.
	(OK_Put_128): Likewise.
	* libgnat/a-ztfiio.adb (OK_Get_32): Likewise.
	(OK_Put_32): Likewise.
	(OK_Get_64): Likewise.
	(OK_Put_64): Likewise
	* libgnat/a-ztfiio__128.adb (OK_Get_32): Likewise.
	(OK_Put_32): Likewise.
	(OK_Get_64): Likewise.
	(OK_Put_64): Likewise.
	(OK_Get_128): Likewise.
	(OK_Put_128): Likewise.