Good point. The Linux driver does the same thing:
tmp = vdc5fb_read(priv, LCLKSELR);
/* Internal parameter setting for LVDS PLL */
tmp |= LVDS_SET_TST(0x0008);
vdc5fb_write(priv, LCLKSELR, tmp);
But, maybe the person that wrote this driver used lcd_setttings.c as sample code as well.
But, since many systems are using '8' instead of '0x10', you might want to just stick with '8' for now to be safe.
If I ever find out the real answer, I'll post it.
Chris