staging: gasket: unify multi-line string

Fix three checkpatch.pl warnings of 'quoted string split across lines'
in gasket_core.c by merging the strings in one line.
Though some strings
are over 80 characters long, fixing this warning is necessary to ease
grep-ing the source for printk.

Signed-off-by: Kaaira Gupta <kgupta@es.iitr.ac.in>
Link: https://lore.kernel.org/r/20200212175826.GA5967@kaaira-HP-Pavilion-Notebook


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