Revert "ANDROID: sysrq: add vendor hook for sysrq crash information"

This reverts commit 0d8928ed.

The hook android_vh_sysrq_crash is not used by any vendor, so remove
it to help with merge issues with future LTS releases.

If this is needed by any real user, it can easily be reverted to add it
back and then the symbol should be added to the abi list at the same
time to prevent it from being removed again later.

Bug: 203756332
Bug: 170234110
Cc: Sangmoon Kim <sangmoon.kim@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I1b4b9280081e0fb569bb74c7f0d3efcb18728b48