DEVELOPERS: remove Sam Bobroff

His e-mail address is bouncing:

   ----- The following addresses had permanent fatal errors -----
<sbobroff@linux.ibm.com>
    (reason: 550 5.1.1 <sbobroff@linux.ibm.com>: Recipient address rejected: User unknown in local recipient table)

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit 374fe52bb0424b8ade4e276dd1aa6bb06f16c17f)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

DEVELOPERS

@@ -1875,10 +1875,6 @@ F:	package/mariadb/
 N:	Ryan Wilkins <ryan@deadfrog.net>
 F:	package/biosdevname/
 
-N:	Sam Bobroff <sam.bobroff@au1.ibm.com>
-F:	arch/Config.in.powerpc
-F:	package/librtas/
-
 N:	Samuel Martin <s.martin49@gmail.com>
 F:	package/armadillo/
 F:	package/canfestival/