sel4: limit max relocation memory to 256M

relocation is required, to avoid overlapping phdr in the elf binaries, but
sel4 will fail to boot if bender relocates the images at the end of physical
memory. Limit the physical relocation address to a fixed 256M value, so that
sel4 will work.

Issue #2451

tool/run/boot_dir/sel4

@@ -52,7 +52,7 @@ proc run_boot_dir {binaries} {
 		puts $fh "timeout 0"
 		puts $fh "default 0"
 		puts $fh "\ntitle Genode on seL4"
-		puts $fh " kernel /boot/bender norelocate"
+		puts $fh " kernel /boot/bender phys_max=256M"
 		puts $fh " module /sel4 disable_iommu"
 		puts $fh " module /image.elf"
 
@@ -71,7 +71,7 @@ proc run_boot_dir {binaries} {
 		# Generate pulsar config file
 		#
 		set fh [open "[run_dir]/config-52-54-00-12-34-56" "WRONLY CREAT TRUNC"]
-		puts $fh " exec /boot/bender norelocate"
+		puts $fh " exec /boot/bender phys_max=256M"
 		puts $fh " load /sel4 disable_iommu"
 		puts $fh " load /image.elf"
 		close $fh