MdeModulePkg/Spi: Solving potential null ptr deref. in SpiNorFlashJedecSfdp

The pointer `Instance->SfdpBasicFlash` can be used before initializing.

Example code flow:
- CreateSpiNorFlashSfdpInstance: Allocate pool for `Instance`
    - InitialSpiNorFlashSfdpInstance
        - ReadSfdp
            - ReadSfdpHeader
                - FillWriteBuffer: Dereferencing
`Instance->SfdpBasicFlash`
            - ReadSfdpBasicParameterTable: Allocate pool for
`Instance->SfdpBasicFlash`

Check both `Instance` and `Instance->SfdpBasicFlash` should have
a non null value before dereferencing it. Otherwise use the defaut
value 0.

Also terminate the function if `Instance` or `WriteBuffer` is NULL.

Signed-off-by: Paddy Deng <v-paddydeng@microsoft.com>

0 files changed, 0 insertions, 0 deletions