When building a separate subprogram declaration for possible inlining of
local subprograms in GNATprove mode, correctly mark subprogram parameters
as coming from source.

This has no impact on compilation.

2018-06-11  Yannick Moy  <moy@adacore.com>

gcc/ada/

	* sem_ch6.adb (Build_Subprogram_Declaration): Mark parameters as coming
	from source.

From-SVN: r261423