MAINTAINERS: thead: update Maintainer

Due to personal reasons, I can't maintain T-Head SoCs any more. At the
same time, I would nominate Drew Fustini as Maintainer. Drew contributed
the sdhci support of TH1520 in the past, and is working on the clk
parts. I believe he will look after T-Head SoCs.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Acked-by: Drew Fustini <drew@pdp7.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>

Author: xhackerustc

MAINTAINERS

@@ -19317,7 +19317,7 @@ F:	drivers/perf/riscv_pmu_legacy.c
 F:	drivers/perf/riscv_pmu_sbi.c
 
 RISC-V THEAD SoC SUPPORT
-M:	Jisheng Zhang <jszhang@kernel.org>
+M:	Drew Fustini <drew@pdp7.com>
 M:	Guo Ren <guoren@kernel.org>
 M:	Fu Wei <wefu@redhat.com>
 L:	linux-riscv@lists.infradead.org