udev-rules-rpi: create groups used by 99-com.rules

99-com.rules assigns I2C, SPI, and GPIO devices to the i2c, spi, and
gpio groups, but the recipe does not create them. This causes udev to
warn about unknown groups at boot and prevents the intended ownership.

Create the three system groups when udev-rules-rpi is installed.

Fixes: #1311
Signed-off-by: Keisuke Tsukuda <tkdkei@outlook.jp>

recipes-core/udev/udev-rules-rpi.bb

@@ -8,8 +8,13 @@ SRC_URI = " \
 	"
 SRCREV = "5ce3ef2b7f377c23fea440ca9df0e30f3f8447cf"
 
+inherit useradd
+
 INHIBIT_DEFAULT_DEPS = "1"
 
+USERADD_PACKAGES = "${PN}"
+GROUPADD_PARAM:${PN} = "--system i2c; --system spi; --system gpio"
+
 do_install () {
     install -d ${D}${sysconfdir}/udev/rules.d
     install -m 0644 ${S}/etc.armhf/udev/rules.d/99-com.rules ${D}${sysconfdir}/udev/rules.d/