i2cget: Document the support of I2C block read

Mention I2C block read support in the i2cget(8) manual page, together
with an example.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
1 file changed