freedreno: Set PIPE_CAP_MIN_MAP_BUFFER_ALIGNMENT to 64

Allocations actually have page alignment, but 64 is still a reasonable
value.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Rob Clark <robclark@freedesktop.org>

src/gallium/drivers/freedreno/freedreno_screen.c

@@ -239,6 +239,9 @@ fd_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
 	case PIPE_CAP_ENDIANNESS:
 		return PIPE_ENDIAN_LITTLE;
 
+        case PIPE_CAP_MIN_MAP_BUFFER_ALIGNMENT:
+		return 64;
+
 	default:
 		DBG("unknown param %d", param);
 		return 0;