tegra132: provide more robust array bounds checking

Make sure the array size matches the number of supported
FUNITs. Also remove the FUNIT_NONE enumeration so that
there isn't an empty slot in the array at index 0.

BUG=chrome-os-partner:31251
BRANCH=None
TEST=Built when array wasn't large enough. Compiler threw an error.

Change-Id: I0bb37c51311d202729b7fb9731d6eec0a28dc040
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/212330
Reviewed-by: Furquan Shaikh <furquan@chromium.org>

src/soc/nvidia/tegra132/funitcfg.c

@@ -82,6 +82,8 @@ static const struct funit_cfg_data funit_data[] =  {
 	FUNIT_DATA(SDMMC3, sdmmc3, U),
 	FUNIT_DATA(SDMMC4, sdmmc4, L),
 };
+_Static_assert(ARRAY_SIZE(funit_data) == FUNIT_INDEX_MAX,
+		"funit_cfg_data array not filled out!");
 
 static inline uint32_t get_clk_src_freq(uint32_t clk_src)
 {

src/soc/nvidia/tegra132/include/soc/funitcfg.h

@@ -28,7 +28,6 @@
 #define FUNIT_INDEX(_name)  FUNIT_##_name
 
 enum {
-	FUNIT_NONE = 0,
 	FUNIT_INDEX(SBC1),
 	FUNIT_INDEX(SBC4),
 	FUNIT_INDEX(I2C2),