ARM: DTS: msm: Add E3-M2 LPM mode support for 8996

Currently there is no support of E3-M2 LPM mode.
Add E3-M2 mode to get better power savings on
certain usecases.

Here is the residency after adding E3-M2 mode.

LVT base residency			D3@180 and  D4@11.5ms
------------------			---------------------
Min_us	Max_us	Mode selected		Min_us  Max_us  Mode selected
60	549	WFI(C1)			60      549     WFI(C1)
550		FPC(C4)			550     	FPC(C4)

Min_us	Max_us	Mode selected		Min_us  Max_us  Mode selected
85	1249	L2 CG(D1)		85	179	L2 CG(D1)
1250	1899	L2 GDHS(D3)		180	11499	L2 GDHS(D3)
1900		L2 FPC(D4)		11500		L2 FPC(D4)

Min_us	Max_us	Mode selected		Min_us  Max_us  Mode selected
120		14199	E1-M1		120	249	E1-M1
14200			E4-M3		550	14199	E3-M2
					14200		E4-M3

SLVT base residency			D3@180 and D4@11.5ms
-------------------			--------------------
Min_us	Max_us	Mode selected		Min_us  Max_us  Mode selected
50	499	WFI(C1)			50      499     WFI(C1)
500		FPC(C4)			500     	FPC(C4)

Min_us	Max_us	Mode selected		Min_us  Max_us  Mode selected
80	1349	L2 CG(D1)		80	179	L2 CG(D1)
1350	1899	L2 GDHS(D3)		180	11499	L2 GDHS(D3)
2300		L2 FPC(D4)		11500		L2 FPC(D4)

Min_us	Max_us	Mode selected		Min_us  Max_us  Mode selected
120		14199	E1-M1		120	249	E1-M1
14200			E4-M3		550     14199   E3-M2
					14200		E4-M3

Change-Id: Ie82d0dc5a8d1b386af7a06af3de46dc3c3199ed4
Signed-off-by: Murali Nalajala <mnalajal@codeaurora.org>