MAINTAINERS: Update Albert's email, he's back at Berkeley

When I was adding a MAINTAINERS entry for SiFive's drivers I realized
that Albert's email is out of date -- he's gone back to Berkeley, so his
SiFive email is technically defunct.  This patch updates his entry to a
current email address, hosted at Berkeley.

Signed-off-by: Palmer Dabbelt <palmer@sifive.com>

MAINTAINERS

@@ -12004,7 +12004,7 @@ F:	drivers/mtd/nand/raw/r852.h
 
 RISC-V ARCHITECTURE
 M:	Palmer Dabbelt <palmer@sifive.com>
-M:	Albert Ou <albert@sifive.com>
+M:	Albert Ou <aou@eecs.berkeley.edu>
 L:	linux-riscv@lists.infradead.org
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/palmer/riscv-linux.git
 S:	Supported