kexec/uImage: Introduce uImage_probe_kernel

uImage supports different types of payloads, including kernel,
ramdisks etc. uImage_probe() as of now checks whether the supplied
payload is of type KERNEL ( i.e, IH_TYPE_KERNEL or IH_TYPE_KERNEL_NOLOAD ).

Change this behaviour to return the image type, if it is one of the supported
payloads. This change is in prepartion to support ramdisks in uImage format.

Introduce a uImage_probe_kernel() which can be used by the archs to check if
the supplied payload is one of the KERNEL types.

Signed-off-by: Suzuki K. Poulose <suzuki@in.ibm.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
5 files changed