package/riscv-isa-sim: needs host-dtc

Fix the following build failure raised since the addition of the package
in commit ccfc90e1010e42e6529afae3a5ea8bf7226dabc1:

configure: error: device-tree-compiler not found

Fixes:
 - http://autobuild.buildroot.org/results/d35ff4a0ca0a8463121d717a9727e0d863ca83e8

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

package/riscv-isa-sim/riscv-isa-sim.mk

@@ -8,5 +8,6 @@ RISCV_ISA_SIM_VERSION = 1.1.0
 RISCV_ISA_SIM_SITE = $(call github,riscv-software-src,riscv-isa-sim,v$(RISCV_ISA_SIM_VERSION))
 RISCV_ISA_SIM_LICENSE = BSD-3-Clause
 RISCV_ISA_SIM_LICENSE_FILES = LICENSE
+HOST_RISCV_ISA_SIM_DEPENDENCIES = host-dtc
 
 $(eval $(host-autotools-package))