MAINTAINERS: greybus: Fix typo s/LOOBACK/LOOPBACK

Fixes: f47e07bc5f1a5c48 ("Fix up MAINTAINERS file problems")
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

MAINTAINERS

@@ -5834,7 +5834,7 @@ F:	drivers/staging/greybus/spi.c
 F:	drivers/staging/greybus/spilib.c
 F:	drivers/staging/greybus/spilib.h
 
-GREYBUS LOOBACK/TIME PROTOCOLS DRIVERS
+GREYBUS LOOPBACK/TIME PROTOCOLS DRIVERS
 M:	Bryan O'Donoghue <pure.logic@nexus-software.ie>
 S:	Maintained
 F:	drivers/staging/greybus/loopback.c