MAINTAINERS: update Sibi Sankar's email address

Switch to using oss.qualcomm.com email ID in the MAINTAINERS file.  Also
update mailmap to ensure proper attribution across historical commits.

Link: https://lkml.kernel.org/r/20250926093426.1735334-1-sibi.sankar@oss.qualcomm.com
Signed-off-by: Sibi Sankar <sibi.sankar@oss.qualcomm.com>
Cc: Bjorn Andersson <andersson@kernel.org>
Cc: Carlos Bilbao <carlos.bilbao@kernel.org>
Cc: Jarkko Sakkinen <jarkko@kernel.org>
Cc: Shannon Nelson <sln@onemain.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: Sibi Sankar

.mailmap

@@ -715,7 +715,8 @@ Shuah Khan <shuah@kernel.org> <shuahkhan@gmail.com>
 Shuah Khan <shuah@kernel.org> <shuah.khan@hp.com>
 Shuah Khan <shuah@kernel.org> <shuahkh@osg.samsung.com>
 Shuah Khan <shuah@kernel.org> <shuah.kh@samsung.com>
-Sibi Sankar <quic_sibis@quicinc.com> <sibis@codeaurora.org>
+Sibi Sankar <sibi.sankar@oss.qualcomm.com> <sibis@codeaurora.org>
+Sibi Sankar <sibi.sankar@oss.qualcomm.com> <quic_sibis@quicinc.com>
 Sid Manning <quic_sidneym@quicinc.com> <sidneym@codeaurora.org>
 Simon Arlott <simon@octiron.net> <simon@fire.lp0.eu>
 Simona Vetter <simona.vetter@ffwll.ch> <daniel.vetter@ffwll.ch>

MAINTAINERS

@@ -20710,7 +20710,7 @@ F:	Documentation/devicetree/bindings/power/avs/qcom,cpr.yaml
 F:	drivers/pmdomain/qcom/cpr.c
 
 QUALCOMM CPUCP MAILBOX DRIVER
-M:	Sibi Sankar <quic_sibis@quicinc.com>
+M:	Sibi Sankar <sibi.sankar@oss.qualcomm.com>
 L:	linux-arm-msm@vger.kernel.org
 S:	Supported
 F:	Documentation/devicetree/bindings/mailbox/qcom,cpucp-mbox.yaml