MAINTAINERS: Remove self from powerpc BPF JIT

Stepping down as I haven't had a chance to look into the powerpc
BPF JIT compilers for a while.
Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210827111905.396145-1-sandipan@linux.ibm.com

MAINTAINERS

@@ -3409,7 +3409,6 @@ F:	drivers/net/ethernet/netronome/nfp/bpf/
 
 BPF JIT for POWERPC (32-BIT AND 64-BIT)
 M:	Naveen N. Rao <naveen.n.rao@linux.ibm.com>
-M:	Sandipan Das <sandipan@linux.ibm.com>
 L:	netdev@vger.kernel.org
 L:	bpf@vger.kernel.org
 S:	Maintained