tpm: Export the open/close functions

At present these functions are not accessible outside the TPM library, but
in some cases we need to call them. Export them in the header file and add
a define for the SHA1 digest size.

Also adjust tpm_open() to call tpm_close() first so that the TPM is in a
known state before opening (e.g. by a previous phase of U-Boot).

Signed-off-by: Simon Glass <sjg@chromium.org>

lib/tpm-utils.h

@@ -18,24 +18,6 @@
 #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
- *
- * After all commands have been completed the caller is supposed to
- * call tpm_close().
- *
- * Returns 0 on success, -ve on failure.
- */
-int tpm_open(struct udevice *dev);
-
-/**
- * tpm_close() - Close the current session
- *
- * Releasing the locked locality. Returns 0 on success, -ve 1 on
- * failure (in case lock removal did not succeed).
- */
-int tpm_close(struct udevice *dev);
-
 /**
  * Pack data into a byte string.  The data types are specified in
  * the format string: 'b' means unsigned byte, 'w' unsigned word,