tcg: Fix occasional TCG broken problem when ldst optimization enabled

tcg: Fix occasional TCG broken problem when ldst optimization enabled

is_tcg_gen_code() checks the upper limit of TCG generated code range wrong, so
that TCG could get broken occasionally only when CONFIG_QEMU_LDST_OPTIMIZATION
enabled. The reason is code_gen_buffer_max_size does not cover the upper range
up to (TCG_MAX_OP_SIZE * OPC_BUF_SIZE), thus code_gen_buffer_max_size should be
modified to code_gen_buffer_size.

CC: qemu-stable@nongnu.org
Signed-off-by: Yeongkyoon Lee <yeongkyoon.lee@samsung.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
(cherry picked from commit 52ae646d4a3ebdcdcc973492c6a56f2c49b6578f)

Conflicts:

	translate-all.c

*modified to use non-tcg-ctx version of code_gen_* variables

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>