package/i2c-tools: add upstream post-4.2 i2ctransfer fix

package/i2c-tools: add upstream post-4.2 i2ctransfer fix

i2c-tools 4.2 contained an invalid check, leading to verbose false-positive
warning messages when the variable length ({r,w}?) option is used:

https://www.spinics.net/lists/linux-i2c/msg50032.html
https://www.spinics.net/lists/linux-i2c/msg50253.html

Unfortunately upstream does not make bugfix releases, instead opting to list
such bugfixes on the wiki:

https://i2c.wiki.kernel.org/index.php/I2C_Tools

So add the patch here.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Acked-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>