qcacld-3.0: Code refine for 4 ini items

1) Refine the documentation text of 4 ini items:
   gStaKeepAlivePeriod
   gApKeepAlivePeriod
   gChannelBondingMode5GHz
   gChannelBondingMode24GHz

2) Fix a discrepancy which happens when ini cfg values
   are converted from those defined in enum
   eIniChanBondState to the corresponding values in
   enum ePhyChanBondState.

3) Use the related APIs to setup channel bonding modes
   instead of directly assigning values.

4) Remove the redundant inclusion of the following two
   header files in csr_api_roam.c:
   cfg_ucfg_api.h
   wlan_mlme_api.h

Change-Id: I43c1e5a05bbb34952a5c7bdbde734f4014592c12
CRs-Fixed: 2416991

mlme/dispatcher/inc/cfg_mlme_feature_flag.h

@@ -167,6 +167,18 @@
  *
  * This ini is used to set default channel bonding mode 24GHZ
  *
+ * 0 - 20MHz IF bandwidth centered on IF carrier
+ * 1 - 40MHz IF bandwidth with lower 20MHz supporting the primary channel
+ * 2 - reserved
+ * 3 - 40MHz IF bandwidth with higher 20MHz supporting the primary channel
+ * 4 - 20/40MHZ offset LOW 40/80MHZ offset CENTERED
+ * 5 - 20/40MHZ offset CENTERED 40/80MHZ offset CENTERED
+ * 6 - 20/40MHZ offset HIGH 40/80MHZ offset CENTERED
+ * 7 - 20/40MHZ offset LOW 40/80MHZ offset LOW
+ * 8 - 20/40MHZ offset HIGH 40/80MHZ offset LOW
+ * 9 - 20/40MHZ offset LOW 40/80MHZ offset HIGH
+ * 10 - 20/40MHZ offset-HIGH 40/80MHZ offset HIGH
+ *
  * Related: None
  *
  * Supported Feature: STA
@@ -192,6 +204,8 @@
  *
  * This ini is used to set default channel bonding mode 5GHZ
  *
+ * Values of 0 - 10 have the same meanings as for gChannelBondingMode24GHz.
+ *
  * Related: None
  *
  * Supported Feature: STA

mlme/dispatcher/inc/cfg_mlme_sta.h

@@ -25,13 +25,15 @@
 
 /*
  * <ini>
- * gStaKeepAlivePeriod - Sends NULL frame to AP periodically in
- * seconds to notify STA's existence
+ * gStaKeepAlivePeriod - STA keep alive period
+ *
+ *
  * @Min: 0
  * @Max: 1000
  * @Default: 60
  *
- * This ini is used to send default NULL frame to AP
+ * This ini is used to control how frequently STA should send NULL frames to AP
+ * (period in seconds) to notify AP of its existence.
  *
  * Related: None
  *

mlme/dispatcher/inc/cfg_mlme_timeout.h

@@ -219,7 +219,7 @@
  * @Max: 65535
  * @Default: 20
  *
- * This ini is used to set keep alive period of AP
+ * This ini is used to set keep alive period(in seconds) of AP
  *
  * Related: None.
  *