drivers/tpm/spi: Make tpm_info object local to compilation unit

tpm_info is used only within spi.c so there is no need for exposing it
outside the file.

BUG=b:36873582
BRANCH=None
TEST=Compiles successfully

Change-Id: I178fe1adf07a981609db9dbcb72b4fe27b4bd2a1
Signed-off-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/474106
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
1 file changed