tpm2-util: give PCR 6 a name too

The specs call this TCG PC Client Platform Firmware Profile
Specification says this PCR is owned by the Host Platform Manufacturer,
at various places. Hence let's give it that name.

src/shared/tpm2-util.c

@@ -5008,6 +5008,7 @@ static const char* const pcr_index_table[_PCR_INDEX_MAX_DEFINED] = {
         [PCR_EXTERNAL_CONFIG]     = "external-config",
         [PCR_BOOT_LOADER_CODE]    = "boot-loader-code",
         [PCR_BOOT_LOADER_CONFIG]  = "boot-loader-config",
+        [PCR_HOST_PLATFORM]       = "host-platform",
         [PCR_SECURE_BOOT_POLICY]  = "secure-boot-policy",
         [PCR_KERNEL_INITRD]       = "kernel-initrd",
         [PCR_IMA]                 = "ima",

src/shared/tpm2-util.h

@@ -308,6 +308,7 @@ enum {
         PCR_EXTERNAL_CONFIG     = 3,
         PCR_BOOT_LOADER_CODE    = 4,
         PCR_BOOT_LOADER_CONFIG  = 5,
+        PCR_HOST_PLATFORM       = 6,
         PCR_SECURE_BOOT_POLICY  = 7,
         /* The following names for PCRs 9…15 are based on the "Linux TPM PCR Registry"
         (https://uapi-group.org/specifications/specs/linux_tpm_pcr_registry/) */