At least one interpolation mode must be enable, but the code that checks
this was not checking for perspective center.
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
spi_ps_input_ena = shader->spi_ps_input_ena;
/* we need to enable at least one of them, otherwise we hang the GPU */
if (!G_0286CC_PERSP_SAMPLE_ENA(spi_ps_input_ena) &&
+ !G_0286CC_PERSP_CENTER_ENA(spi_ps_input_ena) &&
!G_0286CC_PERSP_CENTROID_ENA(spi_ps_input_ena) &&
!G_0286CC_PERSP_PULL_MODEL_ENA(spi_ps_input_ena) &&
!G_0286CC_LINEAR_SAMPLE_ENA(spi_ps_input_ena) &&