intel-speed-select: inherit pkgconfig

do_compile fails with:

  cc1: error: include location "/usr/include/libnl3" is unsafe for
  cross-compilation [-Werror=poison-system-directories]

The kernel tools Makefile gets the libnl flags from pkg-config. The
recipe does not inherit pkgconfig, so there is no PKG_CONFIG_SYSROOT_DIR
and the host pkg-config answers with the host include path.

Drop the manual CFLAGS entry, pkg-config now gives the same path.

Signed-off-by: Alper Ak <alperyasinak1@gmail.com>
Signed-off-by: Khem Raj <khem.raj@oss.qualcomm.com>

meta-oe/recipes-kernel/intel-speed-select/intel-speed-select.bb

@@ -6,7 +6,7 @@ for optimized total cost of ownership."
 
 LICENSE = "GPL-2.0-only"
 
-inherit kernelsrc
+inherit kernelsrc pkgconfig
 
 COMPATIBLE_HOST = '(x86_64|i.86).*-linux'
 COMPATIBLE_HOST:libc-musl = 'null'
@@ -17,7 +17,6 @@ do_populate_lic[depends] += "virtual/kernel:do_shared_workdir"
 
 B = "${WORKDIR}/${BPN}-${PV}"
 
-CFLAGS += "-I${STAGING_INCDIR}/libnl3"
 EXTRA_OEMAKE = "-C ${S}/tools/power/x86/intel-speed-select O=${B} CROSS=${TARGET_PREFIX} CC="${CC}" LD="${LD}" AR=${AR} ARCH=${ARCH}"
 
 PACKAGE_ARCH = "${MACHINE_ARCH}"