prima: Reset Maximum allowable size of a beacon frame

While updating probe response template, driver uses
probeRespTemplateLen as the maximum allowable size of beacon frame.
In case if the content of probeRespTemplateLen is greater than
SCH_MAX_PROBE_RESP_SIZE (700) results in Buffer Overflow while
copying probeRespTemplate buffer to local buffer.

Fix is to validate probeRespTemplateLen against maximum allowable
size (SCH_MAX_PROBE_RESP_SIZE) and if probeRespTemplateLen is
greater than maximum then reset to SCH_MAX_PROBE_RESP_SIZE.

Change-Id: Iccc8e63c78b104d0c2ba5a6995e72c47ac8f8e25
CRs-Fixed: 2303693