[fb] Change to embedding PSF file

Moved old PSF parsing code from kernel, and switched to embedding whole
PSF instead of just glyph data to make font class the same code paths
for both cases.

src/drivers/fb/screen.cpp

@@ -0,0 +1,41 @@
+#include "screen.h"
+
+screen::screen(void *addr, unsigned hres, unsigned vres, pixel_order order) :
+	m_fb(static_cast<pixel_t *>(addr)),
+	m_order(order),
+	m_resx(hres),
+	m_resy(vres)
+{
+}
+
+screen::pixel_t
+screen::color(uint8_t r, uint8_t g, uint8_t b) const
+{
+	switch (m_order) {
+	case pixel_order::bgr8:
+		return
+			(static_cast<uint32_t>(b) <<  0) |
+			(static_cast<uint32_t>(g) <<  8) |
+			(static_cast<uint32_t>(r) << 16);
+
+	case pixel_order::rgb8:
+		return
+			(static_cast<uint32_t>(r) <<  0) |
+			(static_cast<uint32_t>(g) <<  8) |
+			(static_cast<uint32_t>(b) << 16);
+	}
+}
+
+void
+screen::fill(pixel_t color)
+{
+	const size_t len = m_resx * m_resy;
+	for (size_t i = 0; i < len; ++i)
+		m_fb[i] = color;
+}
+
+void
+screen::draw_pixel(unsigned x, unsigned y, pixel_t color)
+{
+	m_fb[x + y * m_resx] = color;
+}