buildsystem: remove autotools from sof

This commit doesn't touch tools buildsystem.

Signed-off-by: Janusz Jankowski <janusz.jankowski@linux.intel.com>

rimage/Makefile.am

@@ -1,27 +0,0 @@
-SUBDIRS=keys
-
-bin_PROGRAMS = rimage
-
-noinst_HEADERS = \
-	rimage.h \
-	css.h \
-	cse.h \
-	plat_auth.h \
-	manifest.h \
-	file_format.h
-
-rimage_SOURCES = \
-	file_simple.c \
-	man_apl.c \
-	man_cnl.c \
-	man_kbl.c \
-	man_sue.c \
-	cse.c \
-	css.c \
-	plat_auth.c \
-	hash.c \
-	pkcs1_5.c \
-	manifest.c \
-	elf.c \
-	rimage.c
-