mtd: maps/physmap: fix oops in suspend/resume/shutdown ops

# reboot
...
[ 42.351266] Flash device refused suspend due to active operation (state 0)
[ 42.358195] Unable to handle kernel NULL pointer dereference at virtual address 00000078
[ 42.360060] pgd = c7d9c000
[ 42.362769] [00000078] *pgd=a7d8d031, *pte=00000000, *ppte=00000000
[ 42.372902] Internal error: Oops: 17 [#1]
[ 42.376911] Modules linked in:
[ 42.379980] CPU: 0 Not tainted (2.6.25-rc2-10642-ge8f2594-dirty #73)
[ 42.380000] PC is at physmap_flash_shutdown+0x28/0x54
...
[ 42.380000] Backtrace:
[ 42.380000] [<c0130c1c>] (physmap_flash_shutdown+0x0/0x54) from [<c01207c0>] (platform_drv_shutdown+0x20/0x24)
[ 42.380000] r5:28121969 r4:c0229e08
[ 42.380000] [<c01207a0>] (platform_drv_shutdown+0x0/0x24) from [<c011cd40>] (device_shutdown+0x60/0x88)
[ 42.380000] [<c011cce0>] (device_shutdown+0x0/0x88) from [<c003e8a4>] (kernel_restart_prepare+0x2c/0x3c)
[ 42.380000] r4:00000000
[ 42.380000] [<c003e878>] (kernel_restart_prepare+0x0/0x3c) from [<c003ea00>] (kernel_restart+0x14/0x48)
[ 42.380000] [<c003e9ec>] (kernel_restart+0x0/0x48) from [<c003fdc0>] (sys_reboot+0xe8/0x1f8)
[ 42.380000] r4:01234567
[ 42.380000] [<c003fcd8>] (sys_reboot+0x0/0x1f8) from [<c001aa00>] (ret_fast_syscall+0x0/0x2c)
[ 42.380000] r7:00000058 r6:00000004 r5:00000001 r4:00000000
[ 42.380000] Code: 0a000009 e7953004 e1a00003 e1a0e00f (e593f078)
[ 42.650051] ---[ end trace 6d6c26a0fc3141de ]---
Segmentation fault
INIT: no more processes left in this runlevel

While looping for mtd[i]s, we should stop at the mtd[i] == NULL.

This patch also removes unnecessary "if (info)" checks:
suspend/resume/shutdown ops are executed only if probe() is succeeded, so info
is guaranteed to be !NULL.

Signed-off-by: Anton Vorontsov <[e-mail]>
Cc: David Brownell <[e-mail]>
Cc: David Woodhouse <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/mtd/maps/physmap.c

···
 	int ret = 0;
 	int i;
 
-	if (info)
-		for (i = 0; i < MAX_RESOURCES; i++)
-			ret |= info->mtd[i]->suspend(info->mtd[i]);
+	for (i = 0; i < MAX_RESOURCES && info->mtd[i]; i++)
+		ret |= info->mtd[i]->suspend(info->mtd[i]);
 
 	return ret;
 }
···
 	struct physmap_flash_info *info = platform_get_drvdata(dev);
 	int i;
 
-	if (info)
-		for (i = 0; i < MAX_RESOURCES; i++)
-			info->mtd[i]->resume(info->mtd[i]);
+	for (i = 0; i < MAX_RESOURCES && info->mtd[i]; i++)
+		info->mtd[i]->resume(info->mtd[i]);
+
 	return 0;
 }
 
···
 	struct physmap_flash_info *info = platform_get_drvdata(dev);
 	int i;
 
-	for (i = 0; i < MAX_RESOURCES; i++)
-		if (info && info->mtd[i]->suspend(info->mtd[i]) == 0)
+	for (i = 0; i < MAX_RESOURCES && info->mtd[i]; i++)
+		if (info->mtd[i]->suspend(info->mtd[i]) == 0)
 			info->mtd[i]->resume(info->mtd[i]);
 }
 #else