scsi: move non-emulation specific code to scsi/

util/scsi.c includes some SCSI code that is shared by block/iscsi.c and
hw/scsi, but the introduction of the persistent reservation helper
will add many more instances of this.  There is also include/block/scsi.h,
which actually is not part of the core block layer.

The persistent reservation manager will also need a home.  A scsi/
directory provides one for both the aforementioned shared code and
the PR manager code.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/Makefile.objs b/Makefile.objs
index 3a6914c..9e89100 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -11,7 +11,7 @@
 
 block-obj-y += nbd/
 block-obj-y += block.o blockjob.o
-block-obj-y += block/
+block-obj-y += block/ scsi/
 block-obj-y += qemu-io-cmds.o
 block-obj-$(CONFIG_REPLICATION) += replication.o