Updated deprecated function

sFLASH_WritePage to sFLASH_WriteBytes as noted in https://github.com/spark/core-common-lib/commit/55e0a056ec748968f747a8d07ec9a0fddf44aedc#diff-779c7ec039ee4ca66b5552dd9a74e92bL163
Merge pull request #5 from kennethlimcp/patch-1

Updated deprecated function