Fix PeriodicVignetteFrameProcessor javadoc.

The parameter was removed in a previous CL but wasn't removed
from the javadoc yet.

PiperOrigin-RevId: 444879675

demos/transformer/src/main/java/com/google/android/exoplayer2/transformerdemo/PeriodicVignetteFrameProcessor.java

@@ -60,7 +60,6 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
    *
    * <p>The parameters are given in normalized texture coordinates from 0 to 1.
    *
-   * @param context The {@link Context}.
    * @param centerX The x-coordinate of the center of the effect.
    * @param centerY The y-coordinate of the center of the effect.
    * @param minInnerRadius The lower bound of the radius that is unaffected by the effect.