accel/ivpu: Fix memory leak in ivpu_mmu_reserved_context_init()

Add appropriate error handling to ensure all allocated resources are
released upon encountering an error.

Fixes: a74f4d99 ("accel/ivpu: Defer MMU root page table allocation")
Cc: Karol Wachowski <karol.wachowski@intel.com>
Reviewed-by: Karol Wachowski <karol.wachowski@intel.com>
Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Signed-off-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241210130939.1575610-3-jacek.lawrynowicz@linux.intel.com