fix(boot): fill the boot-screen swatches on BWR/BWY panels (#149)

The footer swatches advertise the colors a panel can produce, but on a
bitplane scheme the black one rendered as an empty outlined box.

The interior fill was skipped for BWR/BWY by an `!useBitplanes` guard. The
guard is unnecessary: swatch codes reach setBootPixelCode(), which at 1 bpp
already clears the bit for code 0 and sets it for code 1 — exactly the black
and white the B/W plane needs. The colored swatch never reaches this path at
all; colorPlanePass paints it on PLANE_1 and continues.

Author: parkghost

src/boot_screen.cpp

@@ -1019,7 +1019,7 @@ bool writeBootScreenWithQr() {
                     ;
                 if (black) {
                     setBootPixelBlack(row, x_native, pitch, bitsPerPixel, colorScheme);
-                } else if (!useBitplanes) {
+                } else {
                     int si = bootSwatchIndex(lx, ly, swatchY0, swatchY1, swatchW, numSwatches, w_log);
                     if (si >= 0) setBootPixelCode(row, x_native, pitch, bitsPerPixel, swatchCode[si]);
                 }