ANDROID: firmware_loader: Replace use of strcpy and strncpy with strscpy

strscpy is better choice than strcpy or strncpy to avoid any buffer underflow
or overflow issues, so, replace use of strcpy and strncpy with strscpy.

Fixes: d551647f ("ANDROID: firmware_loader: Add support for customer firmware paths")

Bug: 202192667
Signed-off-by: Vamsi Krishna Lanka <quic_vamslank@quicinc.com>

Bug: 249684364
(cherry picked from commit 8ef517f3)
Signed-off-by: Lecopzer Chen <lecopzer.chen@mediatek.com>
Change-Id: I0af5e9169ff21f32471a777a43716b8780acdc60