pinctrl/amd: fix gpio irq level in debugfs

According to the AMD BKDG, the GPIO ActiveLevel bits (10:9) map to:
 00 Active High
 01 Active Low
 10 Active on both edges iff LevelTrig (bit 8) == 0
 11 Reserved

The current code has a bug where it interprets 00 => Active Low, and
01 => Active High.

Fix the bug, restrict "Active on both" to just the edge trigger case, and
refactor a bit to make the logic more readable.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/pinctrl-amd.h

@@ -54,6 +54,10 @@
 #define ACTIVE_LEVEL_MASK	0x3UL
 #define DRV_STRENGTH_SEL_MASK	0x3UL
 
+#define ACTIVE_LEVEL_HIGH	0x0UL
+#define ACTIVE_LEVEL_LOW	0x1UL
+#define ACTIVE_LEVEL_BOTH	0x2UL
+
 #define DB_TYPE_NO_DEBOUNCE               0x0UL
 #define DB_TYPE_PRESERVE_LOW_GLITCH       0x1UL
 #define DB_TYPE_PRESERVE_HIGH_GLITCH      0x2UL