libdiskconfig: Use uintptr_t instead of uint32_t

Use uintptr_t instead of uint32_t when pointer is cast
to an integer type.

Change-Id: I03dd4c7ff66611661af466dfb7b393d461bb2d7d
Signed-off-by: Ashok Bhat <ashok.bhat@arm.com>
1 file changed