input: synaptics_fw_update: fix print statements

%zu is the correct printk format specifier when printing size_t types.

Update printks to use %zu for size_t type variables.

Change-Id: Ie556fd14293ecd36143353e575fd5ef22fab20f7
Signed-off-by: Himanshu Aggarwal <haggarwa@codeaurora.org>