Ensure to initialise the index variable.

After enabling CONFIG_INIT_STACK_ALL=Y, kernel crash is observed.
[    5.602434] Call trace:
[    5.602436]  dsi_display_bind+0xbec/0xeb0
[    5.602441]  component_bind_all+0x13c/0x298
[    5.602443]  msm_drm_bind+0x154/0x8f8
[    5.602446]  try_to_bring_up_master+0x220/0x290
[    5.602449]  component_add+0xc0/0x1a8
[    5.602453]  dp_display_probe+0x31c/0x428
[    5.602456]  platform_drv_probe+0x80/0xb8
[    5.602459]  really_probe+0x4c0/0x6a8
[    5.602461]  driver_probe_device+0x74/0x148
[    5.602464]  __driver_attach+0x120/0x1d8
[    5.602466]  bus_for_each_dev+0x8c/0xd8
[    5.602469]  driver_attach+0x2c/0x38
[    5.602471]  bus_add_driver+0x144/0x268
[    5.602474]  driver_register+0x78/0x110
[    5.602476]  __platform_driver_register+0x4c/0x58
[    5.602481]  dp_display_init+0x20/0x58
[    5.602484]  do_one_initcall+0x204/0x410
[    5.602488]  kernel_init_freeable+0x46c/0x538
[    5.602492]  kernel_init+0x18/0x298
[    5.602495]  ret_from_fork+0x10/0x1c
[    5.602497] Code: 9136e129 52801002 9b2826e8 91003500 (b900091f)
[    5.602501] ---[ end trace 3dfb83852f204db5 ]---
[    5.603216] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b

This patch shall avoid crash by ensuring to select
the default display type as primary.

Change-Id: Id70ffafae48214e7514e9bc303909c3294c79ecd
Reviewed-on: https://gerrit.mot.com/1540832
SLTApproved: Slta Waiver
SME-Granted: SME Approvals Granted
Tested-by: Jira Key
Reviewed-by: Igor Kovalenko <igork@motorola.com>
Submit-Approved: Jira Key
Reviewed-on: https://gerrit.mot.com/1697632

msm/dsi/dsi_display.c

@@ -8789,7 +8789,7 @@ static void dsi_display_is_probed (struct dsi_display *display,
 					int probe_status)
 
 {
-	int enable_idx;
+	int enable_idx = 0;
 
 	if (!display->display_type)
 		enable_idx = 0;