char: add missing MODULE_DESCRIPTION() macros

make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/char/ttyprintk.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/char/lp.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/char/nvram.o

Add the missing invocations of the MODULE_DESCRIPTION() macro.

Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Link: https://lore.kernel.org/r/20240603-md-char-misc-v1-1-25d43d6f331d@quicinc.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>