mtd: remove extra retlen assignment

MTD functions always assign the 'retlen' argument to 0 at the very
beginning - the callers do not have to do this.

I used the following semantic patch to find these places:

@@
identifier retlen;
expression a, b, c, d, e;
constant C;
type T;
@@
(
- retlen = C;
|
T
-retlen = C
+ retlen
;
)

... when != retlen
    when exists

(
mtd_read(a, b, c, &retlen, d)
|
mtd_write(a, b, c, &retlen, d)
|
mtd_panic_write(a, b, c, &retlen, d)
|
mtd_point(a, b, c, &retlen, d, e)
|
mtd_read_fact_prot_reg(a, b, c, &retlen, d)
|
mtd_write_user_prot_reg(a, b, c, &retlen, d)
|
mtd_read_user_prot_reg(a, b, c, &retlen, d)
|
mtd_writev(a, b, c, d, &retlen)
)

I ran it twice, because there were cases of double zero assigments
in mtd tests. Then I went through the patch to verify that spatch
did not find any false positives.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/drivers/mtd/tests/mtd_speedtest.c b/drivers/mtd/tests/mtd_speedtest.c
index ecb2878..4d2ed5c 100644
--- a/drivers/mtd/tests/mtd_speedtest.c
+++ b/drivers/mtd/tests/mtd_speedtest.c
@@ -139,7 +139,7 @@
 
 static int write_eraseblock(int ebnum)
 {
-	size_t written = 0;
+	size_t written;
 	int err = 0;
 	loff_t addr = ebnum * mtd->erasesize;
 
@@ -155,7 +155,7 @@
 
 static int write_eraseblock_by_page(int ebnum)
 {
-	size_t written = 0;
+	size_t written;
 	int i, err = 0;
 	loff_t addr = ebnum * mtd->erasesize;
 	void *buf = iobuf;
@@ -178,7 +178,7 @@
 
 static int write_eraseblock_by_2pages(int ebnum)
 {
-	size_t written = 0, sz = pgsize * 2;
+	size_t written, sz = pgsize * 2;
 	int i, n = pgcnt / 2, err = 0;
 	loff_t addr = ebnum * mtd->erasesize;
 	void *buf = iobuf;
@@ -210,7 +210,7 @@
 
 static int read_eraseblock(int ebnum)
 {
-	size_t read = 0;
+	size_t read;
 	int err = 0;
 	loff_t addr = ebnum * mtd->erasesize;
 
@@ -229,7 +229,7 @@
 
 static int read_eraseblock_by_page(int ebnum)
 {
-	size_t read = 0;
+	size_t read;
 	int i, err = 0;
 	loff_t addr = ebnum * mtd->erasesize;
 	void *buf = iobuf;
@@ -255,7 +255,7 @@
 
 static int read_eraseblock_by_2pages(int ebnum)
 {
-	size_t read = 0, sz = pgsize * 2;
+	size_t read, sz = pgsize * 2;
 	int i, n = pgcnt / 2, err = 0;
 	loff_t addr = ebnum * mtd->erasesize;
 	void *buf = iobuf;