samples/hw_breakpoint: fix building without module unloading

stable inclusion
from stable-v5.10.197
commit 7be3a38f0e379ed3a68b293b3518e8ba5f700b32
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I96Q8P

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7be3a38f0e379ed3a68b293b3518e8ba5f700b32



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[ Upstream commit b9080468 ]

__symbol_put() is really meant as an internal helper and is not available
when module unloading is disabled, unlike the previously used symbol_put():

samples/hw_breakpoint/data_breakpoint.c: In function 'hw_break_module_exit':
samples/hw_breakpoint/data_breakpoint.c:73:9: error: implicit declaration of function '__symbol_put'; did you mean '__symbol_get'? [-Werror=implicit-function-declaration]

The hw_break_module_exit() function is not actually used when module
unloading is disabled, but it still causes the build failure for an
undefined identifier. Enclose this one call in an appropriate #ifdef to
clarify what the requirement is. Leaving out the entire exit function
would also work but feels less clar in this case.

Fixes: 910e230d ("samples/hw_breakpoint: Fix kernel BUG 'invalid opcode: 0000'")
Fixes: d8a84d33 ("samples/hw_breakpoint: drop use of kallsyms_lookup_name()")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>