UefiPayloadPkg/Include/Coreboot.h: Remove __packed

The keyword is not defined and will end as public variable beeing declared
in every source that includes the header.

Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>

UefiPayloadPkg/Include/Coreboot.h

@@ -282,6 +282,6 @@ struct cb_tpm_physical_presence {
 	UINT32 ppi_address;	/* Address of ACPI PPI communication buffer */
 	UINT8 tpm_version;	/* 1: TPM1.2, 2: TPM2.0 */
 	UINT8 ppi_version;	/* BCD encoded */
-} __packed;
+};
 
 #endif // _COREBOOT_PEI_H_INCLUDED_