[RS6000] PR88311, mlongcall indirections are optimised away

[RS6000] PR88311, mlongcall indirections are optimised away

Masking CALL_LONG from the cookie was done in order to simplify and
correct length attribute calculations for indirect calls at one point
in my call series tidy when the indirect patterns used alternatives
"0,n" on the cookie operand.  (Leaving the CALL_LONG in place
calculated the wrong length for long calls without fp args.)

This is no longer necessary now that the indirect sysv call patterns
explicitly test for the fp arg bits in their length attribute
expressions.  And without the CALL_LONG to disable insns like
call_value_local_svsv, combine merrily replaces the indirect long call
sequence with a direct call.  As it should.  This patch reinstates
the CALL_LONG bit.

	PR rtl-optimization/88311
	* config/rs6000/rs6000.c (rs6000_call_sysv): Do not mask cookie.
	(rs6000_sibcall_sysv): Likewise.

From-SVN: r267123