x86/sev: Fix operator precedence in GHCB_MSR_VMPL_REQ_LEVEL macro

The GHCB_MSR_VMPL_REQ_LEVEL macro lacked parentheses around the bitmask
expression, causing the shift operation to bind too early. As a result,
when requesting VMPL1 (e.g., GHCB_MSR_VMPL_REQ_LEVEL(1)), incorrect
values such as 0x000000016 were generated instead of the intended
0x100000016 (the requested VMPL level is specified in GHCBData[39:32]).

Fix the precedence issue by grouping the masked value before applying
the shift.

[ bp: Massage commit message. ]

Fixes: 34ff65901735 ("x86/sev: Use kernel provided SVSM Calling Areas")
Signed-off-by: Seongman Lee <[e-mail]>
Signed-off-by: Borislav Petkov (AMD) <[e-mail]>
Link: https://lore.kernel.org/[e-mail]

arch/x86/include/asm/sev-common.h

···
 #define GHCB_MSR_VMPL_REQ		0x016
 #define GHCB_MSR_VMPL_REQ_LEVEL(v)			\
 	/* GHCBData[39:32] */				\
-	(((u64)(v) & GENMASK_ULL(7, 0) << 32) |		\
+	((((u64)(v) & GENMASK_ULL(7, 0)) << 32) |	\
 	/* GHCBDdata[11:0] */				\
 	GHCB_MSR_VMPL_REQ)