TPM: Export wait_for_stat for other vendor specific drivers

Moved wait_for_stat to tpm.c so that other drivers can use it.
Also renamed it to avoid future namespace conflicts.

Signed-off-by: Rajiv Andrade <srajiv@linux.vnet.ibm.com>

diff --cc drivers/char/tpm/tpm.c
Simple merge

diff --cc drivers/char/tpm/tpm.h
Simple merge

diff --cc drivers/char/tpm/tpm_tis.c
Simple merge