treewide: Use struct_size() for devm_kmalloc() and friends

Replaces open-coded struct size calculations with struct_size() for
devm_*, f2fs_*, and sock_* allocations. Automatically generated (and
manually adjusted) from the following Coccinelle script:

// Direct reference to struct field.
@@
identifier alloc =~ "devm_kmalloc|devm_kzalloc|sock_kmalloc|f2fs_kmalloc|f2fs_kzalloc";
expression HANDLE;
expression GFP;
identifier VAR, ELEMENT;
expression COUNT;
@@

- alloc(HANDLE, sizeof(*VAR) + COUNT * sizeof(*VAR->ELEMENT), GFP)
+ alloc(HANDLE, struct_size(VAR, ELEMENT, COUNT), GFP)

// mr = kzalloc(sizeof(*mr) + m * sizeof(mr->map[0]), GFP_KERNEL);
@@
identifier alloc =~ "devm_kmalloc|devm_kzalloc|sock_kmalloc|f2fs_kmalloc|f2fs_kzalloc";
expression HANDLE;
expression GFP;
identifier VAR, ELEMENT;
expression COUNT;
@@

- alloc(HANDLE, sizeof(*VAR) + COUNT * sizeof(VAR->ELEMENT[0]), GFP)
+ alloc(HANDLE, struct_size(VAR, ELEMENT, COUNT), GFP)

// Same pattern, but can't trivially locate the trailing element name,
// or variable name.
@@
identifier alloc =~ "devm_kmalloc|devm_kzalloc|sock_kmalloc|f2fs_kmalloc|f2fs_kzalloc";
expression HANDLE;
expression GFP;
expression SOMETHING, COUNT, ELEMENT;
@@

- alloc(HANDLE, sizeof(SOMETHING) + COUNT * sizeof(ELEMENT), GFP)
+ alloc(HANDLE, CHECKME_struct_size(&SOMETHING, ELEMENT, COUNT), GFP)

Signed-off-by: Kees Cook <keescook@chromium.org>

drivers/rtc/rtc-ac100.c

@@ -317,10 +317,10 @@ static int ac100_rtc_register_clks(struct ac100_rtc_dev *chip)
 	const char *parents[2] = {AC100_RTC_32K_NAME};
 	int i, ret;
 
-	chip->clk_data = devm_kzalloc(chip->dev, sizeof(*chip->clk_data) +
-						 sizeof(*chip->clk_data->hws) *
-						 AC100_CLKOUT_NUM,
-						 GFP_KERNEL);
+	chip->clk_data = devm_kzalloc(chip->dev,
+				      struct_size(chip->clk_data, hws,
+						  AC100_CLKOUT_NUM),
+				      GFP_KERNEL);
 	if (!chip->clk_data)
 		return -ENOMEM;