dev-util/perf: remove unused patch(es)

Signed-off-by: Michael Mair-Keimberger <m.mairkeimberger@gmail.com>
Closes: https://github.com/gentoo/gentoo/pull/11236
Signed-off-by: Aaron Bauman <bman@gentoo.org>

dev-util/perf/files/perf-4.1.5-prefix.patch

@@ -1,43 +0,0 @@
-commit 75e84ab906ef8935cff3df3d8929f1bafea81599
-Author: Lukas Wunner <lukas@wunner.de>
-Date:   Thu Jun 18 13:00:32 2015 +0200
-
-    perf tools: Fix build breakage if prefix= is specified
-    
-    Invoking Makefile.perf with prefix= breaks the build since Makefile.perf
-    hands that variable down to Makefile.build where it overrides
-    
-        prefix       := $(subst ./,,$(OUTPUT)$(dir)/)
-    
-    leading to errors like this:
-    
-        No rule to make target '/usrabspath.o', needed by '/usrlibperf-in.o'
-    
-    Signed-off-by: Lukas Wunner <lukas@wunner.de>
-    Acked-by: Jiri Olsa <jolsa@kernel.org>
-    Cc: David Ahern <dsahern@gmail.com>
-    Fixes: c819e2cf2eb6f65d3208d195d7a0edef6108d5
-    Link: http://lkml.kernel.org/r/5582c48a.84a22b0a.a918.5285SMTPIN_ADDED_MISSING@mx.google.com
-    Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
-
-diff --git a/tools/build/Makefile.build b/tools/build/Makefile.build
-index 10df572..98cfc38 100644
---- a/tools/build/Makefile.build
-+++ b/tools/build/Makefile.build
-@@ -94,12 +94,12 @@ obj-y        := $(patsubst %/, %/$(obj)-in.o, $(obj-y))
- subdir-obj-y := $(filter %/$(obj)-in.o, $(obj-y))
- 
- # '$(OUTPUT)/dir' prefix to all objects
--prefix       := $(subst ./,,$(OUTPUT)$(dir)/)
--obj-y        := $(addprefix $(prefix),$(obj-y))
--subdir-obj-y := $(addprefix $(prefix),$(subdir-obj-y))
-+objprefix    := $(subst ./,,$(OUTPUT)$(dir)/)
-+obj-y        := $(addprefix $(objprefix),$(obj-y))
-+subdir-obj-y := $(addprefix $(objprefix),$(subdir-obj-y))
- 
- # Final '$(obj)-in.o' object
--in-target := $(prefix)$(obj)-in.o
-+in-target := $(objprefix)$(obj)-in.o
- 
- PHONY += $(subdir-y)
-