clocksource: hyper-v: Mark hyperv tsc page unencrypted in sev-snp enlightened guest

Hyper-V tsc page is shared with hypervisor and mark the page
unencrypted in sev-snp enlightened guest when it's used.

Reviewed-by: Dexuan Cui <[e-mail]>
Reviewed-by: Michael Kelley <[e-mail]>
Signed-off-by: Tianyu Lan <[e-mail]>
Signed-off-by: Wei Liu <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/clocksource/hyperv_timer.c

···
 static union {
 	struct ms_hyperv_tsc_page page;
 	u8 reserved[PAGE_SIZE];
-} tsc_pg __aligned(PAGE_SIZE);
+} tsc_pg __bss_decrypted __aligned(PAGE_SIZE);
 
 static struct ms_hyperv_tsc_page *tsc_page = &tsc_pg.page;
 static unsigned long tsc_pfn;