Merge r357348 from the clang 10.0.0 import branch:

Disable new clang 10.0.0 warnings about converting the result of shift
operations to a boolean in tpm(4):

sys/dev/tpm/tpm_crb.c:301:32: error: converting the result of '<<' to a boolean; did you mean '(1 << (0)) != 0'? [-Werror,-Wint-in-bool-context]

WR4(sc, TPM_CRB_CTRL_CANCEL, !TPM_CRB_CTRL_CANCEL_CMD);
                              ^

sys/dev/tpm/tpm_crb.c:73:34: note: expanded from macro 'TPM_CRB_CTRL_CANCEL_CMD'
#define TPM_CRB_CTRL_CANCEL_CMD BIT(0)

^

sys/dev/tpm/tpm20.h:60:19: note: expanded from macro 'BIT'
#define BIT(x) (1 << (x))

^

Such warnings can be useful in C++ contexts, but not so much in kernel
drivers, where this type of bit twiddling is commonplace. So disable it
for this case.

MFC after: 3 days