imxfb: calculate bpix value from bits_per_pixel

#define PCR_BPIX_4	(2 << 25)

#define PCR_BPIX_8	(3 << 25)

#define PCR_BPIX_12	(4 << 25)

#define PCR_BPIX_16	(4 << 25)

#define PCR_BPIX_16	(5 << 25)

#define PCR_BPIX_18	(6 << 25)

#define PCR_PIXPOL	(1 << 24)

#define PCR_FLMPOL	(1 << 23)

#define PCR_LPPOL	(1 << 22)

#include <linux/math64.h>

#include <mach/imxfb.h>

#include <mach/hardware.h>

/*

 * Complain if VAR is out of range.

				lcd_clk / pcr);

	}

	switch (var->bits_per_pixel) {

	case 32:

		pcr |= PCR_BPIX_18;

		break;

	case 16:

	default:

		if (cpu_is_mx1())

			pcr |= PCR_BPIX_12;

		else

			pcr |= PCR_BPIX_16;

		break;

	case 8:

		pcr |= PCR_BPIX_8;

		break;

	}

	/* add sync polarities */

	pcr |= fbi->pcr & ~0x3F;

	pcr |= fbi->pcr & ~(0x3f | (7 << 25));

	writel(pcr, fbi->regs + LCDC_PCR);

	writel(fbi->pwmr, fbi->regs + LCDC_PWMR);