Maintainers: AMD as SPI driver stack maintainer

Signed-off-by: Abner Chang <abner.chang@amd.com>
Cc: Andrew Fish <afish@apple.com>
Cc: Leif Lindholm <quic_llindhol@quicinc.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Reviewed-by: Michael D Kinney <michael.d.kinney@intel.com>

Maintainers.txt

@@ -417,6 +417,11 @@ M: Abner Chang <abner.chang@amd.com> [changab]
 R: Abdul Lateef Attar <AbdulLateef.Attar@amd.com> [abdattar]
 R: Nickle Wang <nicklew@nvidia.com> [nicklela]
 
+MdeModulePkg: SPI driver stack
+F: MdeModulePkg/Bus/Spi/
+M: Abner Chang <abner.chang@amd.com> [changab]
+R: Brit Chesley <brit.chesley@amd.com> [BritChesley]
+
 MdePkg
 F: MdePkg/
 W: https://github.com/tianocore/tianocore.github.io/wiki/MdePkg
@@ -450,6 +455,12 @@ M: Abner Chang <abner.chang@amd.com> [changab]
 R: Abdul Lateef Attar <AbdulLateef.Attar@amd.com> [abdattar]
 R: Nickle Wang <nicklew@nvidia.com> [nicklela]
 
+MdePkg: SPI related C header files
+F: MdePkg/Include/Protocol/Spi*.h
+F: MdePkg/Include/IndustryStandard/SpiNorFlashJedecSfdp.h
+M: Abner Chang <abner.chang@amd.com> [changab]
+R: Brit Chesley <brit.chesley@amd.com> [BritChesley]
+
 NetworkPkg
 F: NetworkPkg/
 W: https://github.com/tianocore/tianocore.github.io/wiki/NetworkPkg