input: misc: hbtp-input: fix uninitialized usage of a variable

It is possible that 'error' variable is used uninitialized. This
change avoids usage of uninitialized usage of the variable.

CRs-fixed: 973871
Change-Id: Ibd6baf84473f2fe0e54bd04b0bbf9387307f97c1
Signed-off-by: Himanshu Aggarwal <haggarwa@codeaurora.org>