post_proc: Fix improper datatype of EQ preset band level value

unsigned int causes negative band level turn out to be extreme large
value, which results in EQ works abnormally due to unexpected parameter
sent.

Change-Id: I81120c604f4e9f23b25d5a45a7b0294fea63d207
CRs-Fixed: 696825
diff --git a/post_proc/equalizer.c b/post_proc/equalizer.c
index c635251..7ddee5e 100644
--- a/post_proc/equalizer.c
+++ b/post_proc/equalizer.c
@@ -52,7 +52,7 @@
                                         "Jazz",
                                         "Pop",
                                         "Rock"
-					};
+};
 
 static const uint32_t equalizer_band_freq_range[NUM_EQ_BANDS][2] = {
                                        {30000, 120000},
@@ -61,7 +61,7 @@
                                        {1800001, 7000000},
                                        {7000001, 20000000}};
 
-static const uint16_t equalizer_band_presets_level[] = {
+static const int16_t equalizer_band_presets_level[] = {
                                         3, 0, 0, 0, 3,      /* Normal Preset */
                                         5, 3, -2, 4, 4,     /* Classical Preset */
                                         6, 0, 2, 4, 1,      /* Dance Preset */