s390/sclp: Add check for get_zeroed_page()

s390/sclp: Add check for get_zeroed_page()

[ Upstream commit 3db42c75a921854a99db0a2775814fef97415bac ]

Add check for the return value of get_zeroed_page() in
sclp_console_init() to prevent null pointer dereference.
Furthermore, to solve the memory leak caused by the loop
allocation, add a free helper to do the free job.

Signed-off-by: Haoxiang Li <haoxiang_li2024@163.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20250218025216.2421548-1-haoxiang_li2024@163.com
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>