lcd: atmel: move atmel-specific fb_put_word to atmel_lcdfb

lcd: atmel: move atmel-specific fb_put_word to atmel_lcdfb

Reduce the amount of platform-specific code in common/lcd.c by moving Atmel
implementation of fb_put_word() to atmel_lcdfb.c. Since we must also have a
default implementation for everybody else, make the remainder of the code
into a weak function.

Signed-off-by: Nikita Kiryanov <[email protected]>
Reviewed-by: Simon Glass <[email protected]>
Acked-by: Bo Shen <[email protected]>
Tested-by: Bo Shen <[email protected]>
Tested-by: Josh Wu <[email protected]>
Cc: Bo Shen <[email protected]>
Cc: Simon Glass <[email protected]>
Cc: Anatolij Gustschin <[email protected]>