Reorder register writes according to the IPU documentation.

The registers are now set in the following order:
* the horizontal and vertical resizing enabled bits in REG_CTRL;
* the horizontal and vertical coefficient counts in REG_RSZ_COEF_INDEX;
* the source and destination image dimensions in REG_IN_FM_GS and REG_OUT_GS;
* the source and destination image stride (bytes per line) in REG_Y_STRIDE and REG_OUT_STRIDE;
* the horizontal and vertical coefficient lookup table in REG_HRSZ_COEF_LUT and REG_VRSZ_COEF_LUT.

Having the resizing enabled first allows the coefficient counts to apply properly; having the coefficient counts set first allows the coefficient configuration to apply properly.

Downscaling and upscaling are more stable with this change.
Merge pull request #7 from Nebuleon/register-ordering

Reorder register writes according to the IPU documentation.