[WCNCR00152848] cfg80211: fix coverity issue

[Description]
Fix error handle of mtk_p2p_cfg80211_add_iface().
Fix coverity defects under os/linux/
 - CID#361758 "RESOURCE_LEAK" in gl_p2p.c:1106
 - CID#16301  "DEREFERENCE_BEFORE_NULL_CHECK" in gl_p2p.c:501
 - CID#361764 "DEREFERENCE_BEFORE_NULL_CHECK" in gl_p2p_cfg80211.c:2540
 - CID#16518  "STRUCTURALLY_DEAD_CODE" in gl_p2p_cfg80211.c:1338
 - CID#15575  "MISSING_BREAK_IN_SWITCH" in gl_p2p_cfg80211.c:2497
 - CID#15575  "MISSING_BREAK_IN_SWITCH" in gl_p2p_cfg80211.c:2505
 - CID#70624  "DEREFERENCE_BEFORE_NULL_CHECK" in gl_p2p_kal.c:1382
 - CID#76762  "UNINITIALIZED_SCALAR_VARIABLE" in gl_vendor.c:843
 - CID#16364  "WRONG_SIZE_ARGUMENT" in gl_wext.c:1342
 - CID#15626  "MIXING_ENUM_TYPES" in gl_wext.c:2380
 - CID#15491  "MIXING_ENUM_TYPES" in gl_wext.c:2380
 - CID#361736 "RESOURCE_LEAK" in gl_qa_agent.c:2376
 - CID#361514 "MEMORY_CORRUPTIONS" in gl_hook_api.c:2510
 - CID#361511 "MEMORY_CORRUPTIONS" in gl_qa_agent.c:2028
 - CID#69918  "NULL_POINTER_DEREFERENCES" in gl_init.c:2464
 - CID#16662 "UNTRUSTED_VALUE_AS_ARGUMENT" in gl_wext.c:3641
 - CID#70040 "OUT_OF_BOUNDS_ACCESS" In gl_wext.c:2958
 - CID#2355254 "DEADCODE" in gl_wext.c:2384,2387,2390,2393
 - CID#2222643 "DEADCODE" in gl_p2p_cfg80211.c:1526
 - CID#2222641 "DEADCODE" in gl_p2p_cfa80211.c:1411

Change-Id: Ieadcb2a797bec3c92bd0058233006235b744e85c
Signed-off-by: Chun Lee <chun.lee@mediatek.com>
CR-Id: WCNCR00152848
Feature: cfg80211
7 files changed