compatibility_matrix: restore P graphics.composer

    </hal>

    </hal>

    <hal format="hidl" optional="false">

    <hal format="hidl" optional="false">

        <name>android.hardware.graphics.composer</name>

        <name>android.hardware.graphics.composer</name>

        <version>2.1-3</version>

        <version>2.1-2</version>

        <interface>

        <interface>

            <name>IComposer</name>

            <name>IComposer</name>

            <instance>default</instance>

            <instance>default</instance>