ptp: MAINTAINERS: drop Jeff Sipek

Emails to Jeff Sipek bounce:

  Your message to jsipek@vmware.com couldn't be delivered.
  Recipient is not authorized to accept external mail
  Status code: 550 5.7.1_ETR
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240327081413.306054-1-krzysztof.kozlowski@linaro.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

MAINTAINERS

@@ -23661,7 +23661,6 @@ F:	drivers/scsi/vmw_pvscsi.c
 F:	drivers/scsi/vmw_pvscsi.h
 
 VMWARE VIRTUAL PTP CLOCK DRIVER
-M:	Jeff Sipek <jsipek@vmware.com>
 R:	Ajay Kaher <akaher@vmware.com>
 R:	Alexey Makhalov <amakhalov@vmware.com>
 R:	VMware PV-Drivers Reviewers <pv-drivers@vmware.com>