auxdisplay: img-ascii-lcd: Fix module autoload

If the driver is built as a module, autoload won't work because the module
alias information is not filled. So user-space can't match the registered
device with the corresponding module.

Export the module alias information using the MODULE_DEVICE_TABLE() macro.

Before this patch:

$ modinfo drivers/auxdisplay/img-ascii-lcd.ko | grep alias
$

After this patch:

$ modinfo drivers/auxdisplay/img-ascii-lcd.ko | grep alias
alias:          of:N*T*Cmti,sead3-lcdC*
alias:          of:N*T*Cmti,sead3-lcd
alias:          of:N*T*Cmti,malta-lcdC*
alias:          of:N*T*Cmti,malta-lcd
alias:          of:N*T*Cimg,boston-lcdC*
alias:          of:N*T*Cimg,boston-lcd

Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>