x86/sev: Change npages to unsigned long in snp_accept_memory()

In snp_accept_memory(), the npages variables value is calculated from
phys_addr_t variables but is an unsigned int. A very large range passed
into snp_accept_memory() could lead to truncating npages to zero. This
doesn't happen at the moment but let's be prepared.

Fixes: 6c3211796326 ("x86/sev: Add SNP-specific unaccepted memory support")
Signed-off-by: Tom Lendacky <[e-mail]>
Signed-off-by: Borislav Petkov (AMD) <[e-mail]>
Cc: <[e-mail]>
Link: https://lore.kernel.org/r/6d511c2[e-mail]

arch/x86/kernel/sev.c

···
 
 void snp_accept_memory(phys_addr_t start, phys_addr_t end)
 {
-	unsigned long vaddr;
-	unsigned int npages;
+	unsigned long vaddr, npages;
 
 	if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
 		return;