tpm: add macros to enhance TPM commands readability

TPM commands are much easier to read/write with these macros that will
transform words or integers into byte strings. This way, there is no
need to call pack_byte_string() while all variable length in a command
are known (and at must 4 bytes, which is a lot of them).

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>

lib/tpm-utils.h

@@ -12,6 +12,12 @@
 /* Internal error of TPM command library */
 #define TPM_LIB_ERROR ((u32)~0u)
 
+/* To make strings of commands more easily */
+#define __MSB(x) ((x) >> 8)
+#define __LSB(x) ((x) & 0xFF)
+#define tpm_u16(x) __MSB(x), __LSB(x)
+#define tpm_u32(x) tpm_u16((x) >> 16), tpm_u16((x) & 0xFFFF)
+
 /**
  * tpm_open() - Request access to locality 0 for the caller
  *