[COMMON] soc: samsung: el3_mon: Use __pa_symbol for _text and _etext

[COMMON] soc: samsung: el3_mon: Use __pa_symbol for _text and _etext

If CONFIG_DEBUG_VIRTUAL=y,

virt_to_phys used for non-linear address: ffffff8008080000 (0xffffff8008080000)
WARNING: CPU: 4 PID: 1 at arch/arm64/mm/physaddr.c:15 __virt_to_phys+0x28/0x60
...
[<ffffff80080a32bc>] __virt_to_phys+0x28/0x60
[<ffffff8008b61774>] exynos_protect_kernel_text+0x28/0x10c

virt_to_phys used for non-linear address: ffffff8008830000 (_etext+0x0/0x10)
WARNING: CPU: 4 PID: 1 at arch/arm64/mm/physaddr.c:15 __virt_to_phys+0x28/0x60
...
[<ffffff80080a32bc>] __virt_to_phys+0x28/0x60
[<ffffff8008b6178c>] exynos_protect_kernel_text+0x40/0x10c

Change-Id: Idf0e69942e2117b31befd71ff212e906df7af370
Signed-off-by: Junho Choi <junhosj.choi@samsung.com>