common/lcd: cosmetic: clean up a bit

common/lcd: cosmetic: clean up a bit

 - Make the brackets of the function calls more consistent
 - Remove really unnecessary brackets
 - Removes the extern from the function definitions
 - Remove curly brackets from single line statements
 - Remove lcd_setmem proto since it is already in common.h
 - Cleanup comments, remove useless comments
 - Remove NOT_USED_SO_FAR ifdef
 - Cleanup coding style

cc: Anatolij Gustschin <agust@denx.de>
Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>
[agust: rebased the original patch]
Signed-off-by: Anatolij Gustschin <agust@denx.de>