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.