Revert "Input: zforce - don't overwrite the stack"

Revert "Input: zforce - don't overwrite the stack"

This reverts commit eb459cfcd63fb42931f678ac61541152342ec312 because
with given FRAME_MAXSIZE of 257 the check will never trigger and it
causes warnings from GCC (with -Wtype-limits). Also the check was
incorrect as it was not accounting for the already read 2 bytes of data
stored in the buffer.