base-hw: move spec/zynq files to zynq_qemu

This is necessary because in contrast to the zynq boards (see specs in genode-world), only zynq_qemu uses UART_0.
These files should thus fall under the zynq_qemu spec.

Fixes #2615

repos/base-hw/lib/mk/spec/zynq_qemu/bootstrap-hw.mk

@@ -1,11 +1,11 @@
-INC_DIR += $(BASE_DIR)/../base-hw/src/bootstrap/spec/zynq
+INC_DIR += $(BASE_DIR)/../base-hw/src/bootstrap/spec/zynq_qemu
 
 SRC_S   += bootstrap/spec/arm/crt0.s
 
 SRC_CC  += bootstrap/spec/arm/cpu.cc
 SRC_CC  += bootstrap/spec/arm/cortex_a9_mmu.cc
 SRC_CC  += bootstrap/spec/arm/pic.cc
-SRC_CC  += bootstrap/spec/zynq/platform.cc
+SRC_CC  += bootstrap/spec/zynq_qemu/platform.cc
 SRC_CC  += hw/spec/arm/arm_v7_cpu.cc
 SRC_CC  += hw/spec/32bit/memory_map.cc