MAINTAINERS: add an entry for HiSilicon 6421v600 drivers

Add an entry for the SPMI, MFD and PMIC parts of the
HiSilicon 6421v600 support.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/14b009ef0255d61eeaf4273e9c36dafdb1e5e12f.1597762400.git.mchehab+huawei@kernel.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

MAINTAINERS

@@ -7903,6 +7903,12 @@ F:	drivers/crypto/hisilicon/sec2/sec_crypto.c
 F:	drivers/crypto/hisilicon/sec2/sec_crypto.h
 F:	drivers/crypto/hisilicon/sec2/sec_main.c
 
+HISILICON STAGING DRIVERS FOR HIKEY 960/970
+M:	Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
+L:	devel@driverdev.osuosl.org
+S:	Maintained
+F:	drivers/staging/hikey9xx/
+
 HISILICON TRUE RANDOM NUMBER GENERATOR V2 SUPPORT
 M:	Zaibo Xu <xuzaibo@huawei.com>
 S:	Maintained