[Ada] Remove extra space around binary operators

[Ada] Remove extra space around binary operators

Style cleanups. Violation initially spotted while reading the code for
UI_Expon; other occurrences found with grep (and examined manually,
because sometimes the extra space is needed for a code layout).

gcc/ada/

	* bindgen.adb, errout.adb, exp_unst.adb, gnatchop.adb,
	libgnat/a-ngcefu.adb, libgnat/a-strunb.adb,
	libgnat/a-stwiun.adb, libgnat/a-stzunb.adb,
	libgnat/a-wtedit.adb, libgnat/g-debpoo.adb, osint.adb,
	sigtramp-vxworks.c, uintp.adb: Remove extra whitespace around +,
	-, *, / and **.