tmrctr: initialize PWM and timer state variables

[FloofyJin]

XTmrCtr_CfgInitialize() does not initialize IsStartedTmrCtr0, IsStartedTmrCtr1, or IsPwmEnabled.

When XTmrCtr instances are allocated on the stack, these members may contain indeterminate values.

This can cause XTmrCtr_PwmEnable() to return without enabling PWM because IsPwmEnabled is non-zero.

Reproduction:

XTmrCtr Timer;
XTmrCtr_Initialize(&Timer, DEVICE_ID);
XTmrCtr_PwmConfigure(...);
XTmrCtr_PwmEnable(&Timer);

The issue disappears if the application performs memset(&Timer, 0, sizeof(Timer)) prior to initialization. This patch initializes the driver state variables inside XTmrCtr_CfgInitialize() which will essentially do the same thing.

[sivadur]

@FloofyJin Thanks for reporting it. We will check and fix if this turns to be a real issue.