package/qt6/qt6serialbus: use the CMAKE_NINJA flag

Use the newly introduce backend option (4cf79d9b71ff5cf2aede3f21e09ade7c7ac59606)
to specify what cmake backend to use, instead of special-coding it's use.

Signed-off-by: Thomas Devoogdt <thomas.devoogdt@barco.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/qt6/qt6serialbus/qt6serialbus.mk

@@ -10,6 +10,8 @@ QT6SERIALBUS_SOURCE = qtserialbus-$(QT6_SOURCE_TARBALL_PREFIX)-$(QT6SERIALBUS_VE
 QT6SERIALBUS_INSTALL_STAGING = YES
 QT6SERIALBUS_SUPPORTS_IN_SOURCE_BUILD = NO
 
+QT6SERIALBUS_CMAKE_BACKEND = ninja
+
 QT6SERIALBUS_LICENSE = \
 	GPL-2.0+ or LGPL-3.0, \
 	GPL-3.0, GFDL-1.3 no invariants (docs)
@@ -21,7 +23,6 @@ QT6SERIALBUS_LICENSE_FILES = \
 	LICENSES/GFDL-1.3-no-invariants-only.txt
 
 QT6SERIALBUS_CONF_OPTS = \
-	-GNinja \
 	-DQT_HOST_PATH=$(HOST_DIR) \
 	-DBUILD_WITH_PCH=OFF \
 	-DQT_BUILD_EXAMPLES=OFF \
@@ -30,16 +31,4 @@ QT6SERIALBUS_CONF_OPTS = \
 QT6SERIALBUS_DEPENDENCIES = \
 	qt6serialport
 
-define QT6SERIALBUS_BUILD_CMDS
-	$(TARGET_MAKE_ENV) $(BR2_CMAKE) --build $(QT6SERIALBUS_BUILDDIR)
-endef
-
-define QT6SERIALBUS_INSTALL_STAGING_CMDS
-	$(TARGET_MAKE_ENV) DESTDIR=$(STAGING_DIR) $(BR2_CMAKE) --install $(QT6SERIALBUS_BUILDDIR)
-endef
-
-define QT6SERIALBUS_INSTALL_TARGET_CMDS
-	$(TARGET_MAKE_ENV) DESTDIR=$(TARGET_DIR) $(BR2_CMAKE) --install $(QT6SERIALBUS_BUILDDIR)
-endef
-
 $(eval $(cmake-package))