tpm: fix byte order related arithmetic inconsistency in tpm_getcap()

You should not do arithmetic with __be32 or __le32 types because
sometimes it results incorrect results. Calculations must be done only
with integers that are in in the CPU byte order. This commit migrates
tpm_getcap() to struct tpm_buf in order to sort out these issues.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>

drivers/char/tpm/tpm.h

@@ -339,17 +339,6 @@ enum tpm_sub_capabilities {
 	TPM_CAP_PROP_TIS_DURATION = 0x120,
 };
 
-struct	tpm_getcap_params_in {
-	__be32	cap;
-	__be32	subcap_size;
-	__be32	subcap;
-} __packed;
-
-struct	tpm_getcap_params_out {
-	__be32	cap_size;
-	cap_t	cap;
-} __packed;
-
 struct	tpm_readpubek_params_out {
 	u8	algorithm[4];
 	u8	encscheme[2];
@@ -399,10 +388,8 @@ struct tpm_startup_in {
 } __packed;
 
 typedef union {
-	struct	tpm_getcap_params_out getcap_out;
 	struct	tpm_readpubek_params_out readpubek_out;
 	u8	readpubek_out_buffer[sizeof(struct tpm_readpubek_params_out)];
-	struct	tpm_getcap_params_in getcap_in;
 	struct	tpm_pcrread_in	pcrread_in;
 	struct	tpm_pcrread_out	pcrread_out;
 	struct	tpm_pcrextend_in pcrextend_in;