CVE-2026-74403: crypto: ccp - Check for page allocation failure correctly in TIO

In the Linux kernel, the following vulnerability has been resolved:

crypto: ccp - Check for page allocation failure correctly in TIO

Sashiko notes:

> if snpallocfirmwarepages() returns NULL under memory pressure, is it > safe to pass it directly to pageaddress()? > > On architectures without HASHEDPAGEVIRTUAL, pageaddress(NULL) might > compute a deterministic but invalid, non-zero virtual address. The > subsequent if (tiostatus) check would then evaluate to true, and > sevtsminitlocked() would dereference the invalid pointer.

Indeed, pageaddress(NULL) will return non-NULL garbage here. Fix this by checking the page allocation itself for NULL, not the resulting virtual address.