x86: add qemu_x86_coverage target

Builds with coverage enabled are in a continuous state
of bit-rot as no CI job enables it. Introduce a dedicated
x86 target that builds with coverage enabled.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>

boards/x86/qemu_x86/qemu_x86_coverage.dts

@@ -0,0 +1,6 @@
+/*
+ * Copyright (c) 2019 Intel Corporation.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include "qemu_x86.dts"

boards/x86/qemu_x86/qemu_x86_coverage.yaml

@@ -0,0 +1,13 @@
+identifier: qemu_x86_coverage
+name: QEMU Emulation for X86 (Code coverage enabled)
+type: qemu
+arch: x86
+simulation: qemu
+toolchain:
+  - zephyr
+  - xtools
+testing:
+  default: true
+  ignore_tags:
+     - net
+     - bluetooth

boards/x86/qemu_x86/qemu_x86_coverage_defconfig

@@ -0,0 +1,23 @@
+# SPDX-License-Identifier: Apache-2.0
+
+CONFIG_X86=y
+CONFIG_SOC_IA32=y
+CONFIG_BOARD_QEMU_X86=y
+CONFIG_CPU_MINUTEIA=y
+CONFIG_IA32_LEGACY_IO_PORTS=y
+CONFIG_HPET_TIMER=y
+CONFIG_HPET_TIMER_IRQ=2
+CONFIG_PIC_DISABLE=y
+CONFIG_LOAPIC=y
+CONFIG_CONSOLE=y
+CONFIG_SERIAL=y
+CONFIG_UART_NS16550=y
+CONFIG_UART_CONSOLE=y
+CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC=25000000
+CONFIG_TEST_RANDOM_GENERATOR=y
+CONFIG_XIP=y
+CONFIG_X86_MMU=y
+CONFIG_DEBUG_INFO=y
+CONFIG_SCHED_SCALABLE=y
+CONFIG_WAITQ_SCALABLE=y
+CONFIG_COVERAGE=y